Why may esomeprazole be considered a 'me-too' drug?

Why may esomeprazole be considered a 'me-too' drug?

a) Because it is comparable in dose, dosage form, and intended use to an already known drug

b) Because it is manufactured by the same company as that of an already known drug

c) Because its structure is identical to an already known drug

d) Because it is a drug which works through the same mechanism as an already known drug