For this case we have the following indirect pronouns:
Te: It is used for the singular of a third person.
Le: It is used for the singular of a third person associated with the personal pronoun "Usted".
Les: It is used for the third person plural associated with the personal pronoun "Usted".
So, we have:
Roberto / you / introduce to / Carolina
Roberto te presento a Carolina.
Carolina / you / introduce to / Manuel
Carolina te presento a Manuel
Mrs. Lainez / you / introduce to / Mauricio and Jose
Senora Lainez le presento a Mauricio y a Jose
Mr. and Mrs. Lainez / you / introduce to / my brother
Senor y Senora Lainez les presento a mi hermano.
Answer:
- Roberto te presento a Carolina.
- Carolina te presento a Manuel
- Señora Lainez le presento a Mauricio y a Jose
- Señor y Señora Lainez les presento a mi hermano.
