Xenophobia : foreigners : :

a.
hydrophobia : sharks

b.
bibliophilia : books

c.
acrophobia : heights

d.
philanthropy : charity

Xenophobia is the hatred or fear of strangers or unusual circumstances/objects. Let us take a look at the provided answers and see which provides the best comparison:

A. hydrophobia : sharks

Hydrophobia is the fear of water. Sharks aren't water, but they live in water. The comparison doesn't exist, so we can move on.

B. bibliophilia : books

Bibliophilia is the love of books, and while there is a bit of a comparison, it is more or less the opposite of the original comparison.

C. acrophobia : heights

Acrophobia is the fear of heights, so there is a definite comparison here with the original. This is most likely correct, but let us examine the last answer anyway.

D. philanthropy : charity

Philanthropy is the compulsion to give money or valuables away to others who may want/need them more than you. In this case, philanthropy and charity are synonyms, so there isn't a real clear comparison to be made.

So your final answer is:

xenophobia : foreigners :: acrophobia : heights

C is your correct answer choice.
Hope that helped =)

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