The answer is D. Common nouns denote a word animal, person, place or thing that do not require specifications and does not need to be capitalized. For the word prophet, it does not indicate a specific prophet name. But since the question asks for the gender of the noun, prophet is a masculine noun meaning it is used for men.
The feminine noun of prophet is prophetess. People can use the word a woman prophet instead of prophetess if they are not sure of its feminine word as both are acceptable. When one will encounter the word prophet, they should use the pronouns he, his or him to show the masculine gender.