Final answer:
The correct pronouns to replace 'Peter and Chris' and 'their own business' are 'they' and 'it' respectively, as 'Peter and Chris' suggests a plural subject, and 'business' is a singular object.
Step-by-step explanation:
The pronouns that can replace 'Peter and Chris' and 'their own business' are 'they' and 'it,' respectively. In grammatical terms, we must use a subjective case pronoun for the subjects and an objective case pronoun for the objects. Therefore, the correct option for the pronouns to replace 'Peter and Chris' and 'their own business' is A. them, it.
It's important to recognize that pronouns must agree in number and case with the nouns they are replacing. 'Peter and Chris' is plural, so the pronoun must also be plural, which is 'they' in the subjective case and 'them' in the objective case. In the case of 'their own business,' the business is singular, so the correct pronoun to replace it is 'it' which is the same in both subjective and objective cases.