The correct form of the verb escribir in the given sentence is 'escribiera.'
The correct form of the verb escribir in the sentence 'He doubted the prince wrote stories for children' is option B) escribiera.
In this context, 'Dudaba que el príncipe escribiera cuentos para niños.' is the correct form in Spanish, showing doubt in the past tense subjunctive mood.
Choosing 'escribiera' aligns with the subjunctive mood required by the verb dudar (to doubt) in this sentence.