The exercise aims for you to practice conjugation in PRESENT of the verb IR, which is an irregular verb, it means it doesn't follow a conjugation rule like other verbs. You need to notice that a conjugation is done with a personal pronoun or also nouns or names.
For example, answer 3 uses a name to conjugate, but answers 2 and 4 use a noun to conjugate (boyfriend and cousin respectively). The other answers use a personal pronoun.
Here is the conjugation of the verb IR in PRESENT.
1)Yo lleve este reloj la semana pasada.
2)¿Cuando encontraste esa corbata?
3)Ayer nosotros oimos esa musica en la fiesta.
4) Juanjo le vendio aquellos libros a Raquel.
