Logical predication; Rhetorical constructionThe sentence explains that the event known as a transit of Venus is an occasion when the outline of the planet is visible. The correct form of the sentence must clarify that the visible outline is a function of this occasion, not the result of some agent’s action.
A. There is no referent for it; to say that the planet Venus makes the outline of the planet visible is nonsensical.
B. Correct. Outline is the appropriate subject for the verb becomes (visible).
C. There is no referent for it. The causal conjunction so is confusing when it immediately follows the appositive phrase an occasion known as a transit of Venus.
D. The string of connecting phrases such that during which is confusing and nonsensical; the relative pronoun which has no referent.
E. The reference of such that is ambiguous when it immediately follows the appositive phrase, an occasion known as a transit of Venus.
The correct answer is B.