The rules of etiquette for formal dinner parties with

The correct answer is (D).
The original sentence (A) suffers from faulty parallelism. The second occurrence of "from" should be deleted to restore the proper parallelism between the phrases "the host" and "the diplomat's." At the same time, the word "both" is redundant in light of the words "the other" at the end of the sentence, thereby confusing the meaning of the sentence.

(B) remedies the original sentence's problems but presents a usage problem. The phrase "each other" should refer to only two persons or things. Because the potential number of "citizens" (guests) might exceed two, "one another" should be used instead.

(C) suggests a nonsensical meaning - that the country itself (rather than a person) seats its citizens. The construction also creates ambiguity as to what the rules require.

(D) remedies the original sentence's faulty parallelism by reconstructing the phrase, using the subjunctive form ("thatтАа be").

(E) is faulty in two respects. It includes the word "to" twice; the second occurrence is redundant and should be omitted. Also, the use of double possessive adjectives ("diplomat's" and "country's") is improper.

Vivek.

Oh well, thx vivek for posting answer with explanation. Was about to provide an explanation to Dharmin but you just nailed it :wink: