The correct option is
C doesn't it
In the given sentence, the question mark indicates that we have to add a question tag in order to make it a question. Thus, the answer must either contain an auxiliary verb matching the auxiliary from the sentence or an alternative form of the auxiliary 'do' in a degree that is opposite to the one in the sentence. Since, the sentence does not contain an auxiliary, the question tag must contain an alternate form of the auxiliary 'do'. Also, the answer must be in a negative degree as the sentence is positive. Further, it must contain a pronoun that refers to the 'hot summer'.
Option A is incorrect. 'isn't it' is in the negative degree and the pronoun it also refers to the object of the sentence, but, the auxiliary 'is' is incorrect as the required auxiliary in the sentence must be the auxiliary 'do'. Thus, the answer is grammatically incorrect.
Option B is incorrect. 'is there' is in the positive degree. Further, the pronoun 'there' does not refer to the object of the sentence. Further, the auxiliary 'is' is not a form of the auxiliary 'do'. Thus, the answer is incorrect.
Option C is correct. 'doesn't it' is in the negative degree and also has the pronoun 'it' that refers to the object of the sentence. Further, the auxiliary 'does' is a form of the auxiliary 'do'. Thus, it is the correct answer.
Option D is incorrect. 'does there' is in the positive degree. Further, the pronoun 'there' does not refer to the object of the sentence. Thus, the answer is incorrect.