Select the correct indirect form of the given sentence.

Sitab asked his mother, “Has it been snowing all night?”

Sitab asked his mother if it had been snowing all night.

The correct indirect form of the given sentence is:

Sitab asked his mother if it had been snowing all night.

When changing from direct speech to indirect speech, there are a few rules that must be followed. One of these rules is that the tense of the reported speech must be changed to the past tense. In this case, the direct speech is in the present perfect tense ("Has it been snowing"), so the indirect speech must be in the past perfect tense ("had been snowing").

The other options are incorrect because they use the wrong tense.

• Sitab asked his mother if it has snowed all night. This is in the present perfect tense, which is incorrect for a question about something that happened in the past.
• Sitab asked his mother if it is snowing all night. This is in the present tense, which is also incorrect for a question about something that happened in the past.
• Sitab asked his mother if it was snowing all night. This is in the past tense, but it is incorrect because the question is asking about the entire night, not just a specific moment in time.