In 1876, three years before Edison patented the electric bulb,

Heya there!
Your approach is absolutely correct. This question primarily focuses on the concept of double past structure which is done properly in the original sentence itself. And by simply paying attention to the intended meaning of the sentence, one can easily eliminate the incorrect choices.
You did the question well!

Dear Friends,

Here is a detailed explanation to this question-


Choice A: This answer choice maintains proper tense use, conveys the intended meaning of the sentence, and is quite concise. Thus, this answer choice is correct.

Choice B: This answer choice incorrectly uses the past perfect tense to refer to the later of two events, Edison's patenting of the electric bulb. Thus, this answer choice is incorrect.

Choice C: This answer choice incorrectly implies that Edison patented the electric bulb in 1876; the correct meaning of the sentence is that Alexander Graham Bell invented the telephone in 1876, three years before Edison patented the electric bulb. Thus, this answer choice is incorrect.

Choice D: This answer choice also implies that Edison patented the electric bulb in 1876, through the clause "Before Edison...in 1876". This answer choice also incorrectly implies that Edison patented the bulb, over three years. Thus, this answer choice is incorrect.

Choice E: This answer choice repeats the tense-error found in Option A. Additionally, this answer choice's use of the phrase "obtained the patent rights for the electric bulb" is needlessly wordy. Thus, this answer choice is incorrect.

Hence, A is the best answer choice.

To understand the concept of "Past Perfect Tense - Use of Had on GMAT", you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team

eakabuah ExpertsGlobal generis GMATNinja
Who/what decides that Edison didn't patent the bulb in 1876.
Any other reason for C to be incorrect?

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Hello deveshj21,

We hope this response finds you well. Please find below, a detailed answer to your doubt.

A close reading of the original sentence, particularly the phrase "In 1876, three years before Edison patented", will show that the year 1876 was the year when Alexander Grahm Bell invented the telephone and three years before Edison patented the electric bulb.

Beyond this error, there is no issue with Option C. Option C is grammatically correct, its only issue is that it alters the intended meaning of the sentence.

Hope this explanation was able to resolve your doubt.

All the best!
Experts' Global Team

ExpertsGlobal
Thankyou for the Swift reply.
but I beg to differ: why can't Edison invent the bulb in 1876-speaking completely in terms of logic.

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Hello deveshj21,

From a strictly logical perspective, there is no reason that Edison could not have patented the electric bulb in 1876; however, the sentence informs us that he did not. In this sentence, "1876" is modified by the phrase "three years before Edison patented"; thus, we can logically infer that Edison patented the electric bulb three years after 1876.

Hope this helps.

All the best!
Experts' Global Team