Approved April 24, 1800, the act of Congress that made

Hi dave13 and teaserbae ,

(I am not the expert from Magoosh, but I am replying to your callout from yesterday.)

Although sumit411 is partly correct about GMAC's preference for modifiers that are not back-to-back, the rules that govern the different types of possible combinations are complex and subject to exceptions and variations that make my head hurt.

Options B and D can be eliminated on fairly straightforward grounds.

This question tests logical predication and parallelism.

The sentence is supposed to describe two separate things about an act of Congress.

Fact #1: the act was passed on April 24, 1800.

Fact #2: its provisions made two things happen: "A" (moved the government to a new city); and "B" (established the Library of Congress)

Both options B and D fail at that descriptive task.

Look at the modifiers.

Essential and nonessential modifiers (and "that" vs. "which")

Note: in this post, "restrictive" and "essential" are interchangeable. Similarly, "non-restrictive" and "nonessential" are interchangeable.

The modifiers in B and D are set off by commas. The modifiers, therefore, allegedly are not essential.

Logically, however, the modifiers are essential to convey the two different facts about the act (when it was passed and what it did).

The absence of commas signals that a modifier is restrictive. Only restrictive modifiers are not set off by commas.
Stated differently, only essential modifiers have no commas.

Hence the "THAT without commas" construction signals an essential part of the sentence. Removing an essential modifier changes the core of the sentence.

The "WHICH + commas" construction indicates that the information is not essential to the core of the sentence and can be removed without changing the meaning of the sentence.

So -- remove the "comma WHICH" clause from B (allegedly that "which" clause merely provides some extra information). We have:

(B) The act of Congress making provision for the removal of the government of the United States to the new federal city, Washington, D.C., also established the Library of Congress.

Incorrect. We can't just remove the date on which an important piece of legislation was approved! When it was approved makes a difference to the meaning of the sentence.

Option B also sets off "making provision for" with commas. We will remove that modifier, too -- right below, in option D.

In Option D, again we have an allegedly nonessential modifier ("making provision for" is set off by commas). Remove that phrase.

(B) and (D): The act of Congress also established the Library of Congress.

Definitely not correct. (Date of approval? First provision of the act? We cannot have an "also" without a second something to which the "also" refers.)

Parallel verb forms

In addition, if you missed the modifier issue (learn about essential and nonessential modifiers HERE), the verb forms that describe the act's provisions are not parallel in options B and D.

As both original options stand, we have:

X makING provision for A . . . and establishED B

(We can use "and" in place of "also" in discussing the contents of the act in these two options. The comma that precedes "also" exists only because a city and its territory are named. If the sentence used "new city" instead of "Washington, D.C.," there would be no comma before "also.")

MakING and establishED are not parallel. The CORRECT construction is:

X made provision for A and established B

OR (in correct option A): The X that made provision for A also established B.

The weird modifier: [date], making?

Finally, most of the time, a comma + ___ ING (present participle modifier) refers to whatever precedes it. B and D say:

. . . April 24, 1800, making . . .

The date that the act was passed and the content of the act have nothing to do with each other.
The modifier is illogical at best.

Avoid confusion, remember the "touch" rule, and use option A as a benchmark

Okay, I fibbed. I have one more thought. We should think explicitly about the "touch" rule. (So far we have been using the rule tacitly.)

The "touch" rule states that a noun and its modifier should be placed next to each other, and if that construct is not possible they should be placed as close together as possible.

Remember the reason for the rule. A sentence may contain many nouns. If the sentence also contains noun modifiers, the reader needs to know which noun is being modified (and by which modifier).

The basic idea is very simple. If I am writing some information about something, I should put that information close to what I am writing about.

Answer A sets the two important facts about the act right next to the act. The two separate facts are placed right before and right after "the act."
Option A uses the essential modifier THAT and thus is crystal clear that all of the information contained in the description of the act's provisions is vital.

Although finding four wrong answers is the best strategy, sometimes that strategy must include comparing answers.
Whittle down the options. Compare those that remain. (Ideally none remain, but that scenario will not happen every time.)

Some very hard SCs may look as if no answer could be correct. In this case, however, at the least option A is a clear possibility.

As you try to sort through all the issues that B and D present, remember to compare what you like with options that have no glaring errors.

dave13 and teaserbae - I hope that answer helps.

If not, ask your question a bit more specifically and we'll be glad to help.