The correct option is
D likes
In order to fill in the blank with the correct form of the verb, we must understand the tense of the sentence.In the given sentence, the words 'has nightmares afterwards' explain to us that the sentence is a general statement, as it usually or always happens. Hence, we can say that the sentence is in the simple present tense. In the simple present tense, the verb is usually in its original form or in the third person form, depending on the subject.
NOTE: 'Watching' is an object here and not a verb. Hence, the tense of the sentence can't be judged by this word.
Option A - 'Liked' is the past form of the verb 'like'. As the given sentence is in simple present tense, we can't use past form of the verb here. Hence, option A is incorrect.
Option B - As 'Kriti' is a third person, the verb should be in the third person form as well. 'Like' is the first/second person form of the verb. Hence, option B is incorrect.
Option D - 'Has liked' is the present perfect tense and we need a verb in simple present tense. Hence, option D is incorrect.
Option C - 'Likes' is the third person form of the verb 'like' that matches with the subject as well. Hence, option C is the correct answer.
'Kriti likes watching horror films although she has nightmares afterwards.'