Identify the error part in the sentence: Today she was an accomplished (a) / singer because she had trained (b) / under an acclaimed guru in her youth. (c) / No error. (d)

The error lies in part (a). The sentence describes a present-day quality of the singer based on past training. The correct form should be 'Today she is an accomplished singer' (present tense) because the statement refers to her current status. Using 'was' incorrectly shifts the entire statement to the past, contradicting the time marker 'today'.