For this case we can translate the sentence given as:
I'm Marta _________ ________ garden
We must complete the sentence with the proper conjugation of the verb "ir", in addition to the correct article.
We have indicative present mode:
Yo voy
Tú vas
él/ella/eso va
Nosotros vamos
Vosotros vais
Ellos van
It is noted that the sentence is in the first person, so we discard options A and B.
On the other hand, in Spanish, the preposition "a" followed by the article "el", produces a contraction, that is, the article "al".
Example:
Ellos van al restaurante.
Then, if we complete the sentence we have:
I am Marta. I go to the garden.
Soy Marta. Voy al jardín.
Answer:
Option C