The correct answer is Were the clothes ironed by her?.
In English transformational grammar, converting an interrogative sentence from the active voice to the passive voice requires strict adherence to tense preservation and syntactic restructuring. The original prompt is formulated in the simple past tense, marked by the auxiliary verb \"Did\". When converting a simple past question into the passive voice, the structural formula demands using the past tense form of the verb \"to be\" (was/were) combined with the plural grammatical subject (\"the clothes\") and the past participle of the main verb (\"ironed\").
The alternative distractor choices introduce errors in tense, aspect, or grammatical voice structure. For instance, Were the clothes being ironed by her? incorrectly introduces the past continuous aspect, which changes the original meaning. The choice Are the clothes ironed by her? shifts the sentence into the present tense, violating the rule of tense preservation. Lastly, Had the clothes ironed by her? creates an ungrammatical past perfect construction that lacks the required passive auxiliary. Therefore, option two is the only syntactically flawless conversion.