Which is a sentence fragment?

it’s overdue.

watching a scary film with my friends at the theater.

if you do not understand, ask your teacher for .

call me.

Watching a scary film with my friends at the theater is the sentence fragment.

the second option

Explanation:

The sentence fragment in the options provided is the second one. "Watching a scary film with my friends at the theater" lacks a verb, which is the main characteristic of a sentence. The use of sentence fragments takes place more commonly in daily oral interaction to reply to someone's question for example. This phrase might answer the question "What do you like doing in your free time?". If the fragment were used in written form, context and details would be necessary, however, informal speaking is more benevolent and does not always require complete ideas or a strict grammatical convention.