Respuesta :
Correct answer:
b. Anita es menor que Marta.
Since Marta is 15 years old and Anita is 14 years old, thereforeAnita is younger than Marta. So in this sentence we use the form menor que after the conjugation of the verb ser for the third person singular in the simple present, which is es. Finally:
Anita es menor que Marta