Which type of figurative language is used in this sentence?

The Sahara Desert is a sandy oasis.

Metaphor

Explanation:

Figurataive language is word, group of words or phrase which does not depict its literal meaning in the sentence. Figurative language is used by writers to make their literary work more attractive and interesting.

Metaphor is a type of figurative language in words are used to one object with other to depict similarity in them. Here metaphor does not depict the literal meaning but expresses the abstract idea about the object in consideration.  

Example : Hercules is a human beast.  

Here beast is used as metaphor. It does not mean that Hercules is beast but he possesses power and strength which is much similar to beast.

Similarly, in the sentence mentioned in the problem statement, Sahara desert is referred as sandy oasis. Here oasis is metaphor. It expresses the idea that Sahara desert has features similar to that of oasis.

The sentence means to say  that just as oasis is a semi-desert area which can be cultivated and is habitat for certain kind of animals and plants. Similarly in Sahara desert natural habitat of plants and animal persist.

the correct answer is political prisoners

i think it would be reparing roads