Final answer:
The synonym for 'sagacity' is 'wisdom', and the word closest in meaning to 'hypothesis' is 'suggestion'. Both 'sagacity' and 'hypothesis' refer to elements of understanding and proposing insights, but 'sagacity' is about having wisdom whereas a 'hypothesis' is a yet-to-be-validated suggestion or theory.
Step-by-step explanation:
The nearest synonym for the word 'sagacity' is wisdom. Therefore, the correct answer is a) Wisdom. The word 'sagacity' refers to the quality of being sagacious; that is, having or showing keen mental discernment and good judgment. It is similar in meaning to having wisdom or wise insight into situations.
To address the other part of the question, which asks about the word closest in meaning to 'hypothesis', the most suitable choice is d) suggestion. A hypothesis is a proposed explanation for a phenomenon that has not yet been proven to be true. It is a tentative insight into the natural world; a theory that is yet to be tested and validated.