i don't understand the question

Question

"¿Recibió su nieto la carta que le enviaste?" "No sé. Nunca me contestó. Voy a escribirle _____.
a. especial
b. de nuevo
c. desde que nació
d. a los 12 años

(did you receive your grandson's letter?)??

Answer 1

Yes, "Did your grandson receive the letter that I sent to him? I don't know. He never answered me. I'm going to write him......."

a. special
b. again
c. since he was born
d. at 12 years (of age)

Sra

"de nuevo" is a synonym for "otra vez"