The given sentence is an interrogative sentence.
According
to the rules of narration and reporting, if the reporting verb is in
the past tense, the tense of the reported verb is changed into its
corresponding past form. The reporting verb in the given sentence,
'said', is in the past form. Therefore, the reported verb, 'are' will
change into 'was'. The second person pronoun 'I' will change into the person of the speaker.. In an interrogative sentence, in the indirect speech the helping verb is put after the subject.
Thus, in indirect speech the sentence must be,
She asked if i was ready.
Thus option A is the correct answer.
Options B,C,D are incorrect as they do not follow the rules of Narration and Reporting.