The correct option is B Is/sold
A sentence in passive voice focuses on the person or thing that receives an action rather than the person/thing that performs the action.
For example, 'My room was cleaned by me.'
The basic structure of an interrogative sentence in the passive voice is:
the appropriate form of the verb 'to be' + subject + past participle: Was the room cleaned by you?
(As the tense changes, the structure varies.)
The given interrogative is in the simple present tense.
Option B: 'Is ice cream sold here' is the appropriate structure formed with the words in this option. Hence option B is correct.
Option A: 'Does...sell' is in the active form, it changes the thing 'ice cream' to perform, rather than receive, the action. Hence A is incorrect.
Option C: This combination is incorrect. 'Do' is in present tense whereas 'sold' is in the past. Hence C is incorrect.
Option D: The verb 'sell' is the base form of the verb whereas in the passive form, the past tense form of the verb is required. Hence D is incorrect.
(The passive form in the simple present tense uses a past participle 'sold' rather than the base verb 'sell'.)