The correct option is A. He picked up a piece of fruit out of the bowl and bit into it.
A is an indefinite article as well as AN. A is the correct indefinete article for this sentence because when the following word, usually a noun, begins with a consonant, the suitable article employed is "A". "An" will be used in the case of a word which first letter is a vocal.
"The" cannot be the correct answer as it is not an indefinite article, It is a DEFINITE article, which consists on an article to refer to a particular object that had been already mentioned.
What can you infer from the way Cabeza de Vaca responds to the Native Americans' show of compassion for the Spaniards after the boat capsizes? Despite having been shown great hospitality by the Native Americans, Cabeza de Vaca still considers them "crude and untutored people."