Topic: Right Form of Verb,

Best Answer Explained in Below-:

In the sentence "He decided to take a taxi lest he — be late," the word "lest" indicates a concern about a possible future outcome, specifically avoided situations. Lest is used to express the intention of preventing something undesirable from happening.

Among the options provided, "should" is the most appropriate choice because it conveys a sense of obligation or necessity. In this context, using "should" suggests that his being late is a consequence he wants to avoid; it implies a future scenario that could logically result from taking no action (in this case, not taking a taxi).

The other options, "may," "might," and "would," also express possible outcomes but do not fit as smoothly with the preventative context indicated by "lest." "May" and "might" indicate possibility but lack the necessity of avoidance, while "would" suggests a conditional action based on a prior state. Therefore, "should" effectively captures the proactive stance he takes to prevent the likely consequence of being late, making it the correct choice in this sentence.