Answer:
1.La Maison es un mercado al aire libre. <em>b. falso </em>
2.La Maison vende ropa muy elegante y nueva. <em>a. cierto </em>
3.Guido Asenjo Puebla diseña ropa y también pinta (paints). <em>a. cierto </em>
Tú casa es grande.

The difference between "tú" and "usted" depends on the formality. "Tú" is used <u>when talking to friends or relatives (informal)</u> while "usted" is used <u>when talking to older people or a person of high social rank (formal)</u>.
In this case we want to write the <u>informal</u> form of "tú", so we use "tú". Also, when dealing with <u>permanent states</u>, the verb "ser" (to be) is used.
I think it's Religious figures.
Hope that helped