I believe the answer is B
B. Libre
En mi tiempo libre me gusta tocar la guitarra, leer, y escribir poemas.
In my free time, I like to play guitar, read, and write poems.
Sexto (6), séptimo (7), octavo (8), noveno (9)
These are the ordinal numbers rather than the cardinal numbers normally used.
Translating the sentence, we get something along the lines of Raul ____ the pen to write. There's one word we can see falls into the blank, and that's used. Now all wee need to do is translate used into Spanish. One way to say used in Spanish is usado, so usado is the word that best completes the sentence.
