A singular subject takes a singular verb, while a plural subject takes a plural verb. Here the subject, "jeans", is in plural form. Therefore, the Verb applied will also be in plural form.
Option A is correct because in the word "are looking", "are" is a plural verb. Following it, the application of "Present Continuous verb", i.e., are + V4 (looking) in this sentence is appropriate.
Option B is correct because the word "look" is a plural verb.