1. choose the correct present tense conjugation of the verb tener for the following subject pronoun.
yo
a. tienes
b. tenemos
c. tienen
d. tengo

2. choose the correct present tense conjugation of the verb tener for the following subject pronoun.
ustedes
a. tenéis
b. tengo
c. tenemos
d. tienen

3. which sentence is incorrect.
a. nosotros ponemos los libros en la mesa.
b. yo pono los libros en la mesa.
c. yo pongo los libros en la mesa.
d. ella pone los libros en la mesa.

Yo is the subject pronoun that matches the first person singular. Therefore, we must choose a word that is a conjugation of the verb tener for this person, too, in the simple present. From the list, tienes matches the second person singular (tú) in the simple present, tenemos matches the first person plural (nosotros) in the simple present and tienen matches the third person plural (ellos/ellas) and the second person plural (ustedes) in the simple present, Finally, tengo matches the first person singular (yo) in the simple present and this is the correct answer.

Ustedes is the subject pronoun that matches the second person singular. This subject pronoun is used in formal way in Spain, but in other countries is used both in formal and informal way. From the list, tenéis matches the second person plural in informal way (vosotros) in the simple present, tengo matches the first person singular (yo) in the simple present and tenemos matches the first person plural (nosotros). Finally, tienen matches the second person plural (ustedes) in the simple present and this is the correct answer.

This is the incorrect sentence because pono is not a correct conjugation of the verb poner. The correct conjugation would be yo pongo los libros en la mesa, so here this sentence stands for the first person singular in the simple present. Therefore, pongo is the correct conjugation of the verb poner that matches yo in the simple present.