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.
Fill in the blank basically
Me llamo ____ (your name)
Yo tengo ___ años (your age)
Mis padres son buenos (how are your parents)
Yo desayuno y veo tv (what you do every morning)
Mis amigos salen a comer el fin de semana (what your friends do on the weekends)
Letter C is the correct Cantamela