Answer:
They helped expand their territory.
They kept trade networks open.
They protected them from rival tribes.
Step-by-step explanation:
Marriage alliances helped Chickasaw in different ways such as it helped in expanding their territory, kept trade networks open, and protected them from rival tribes.
Chickasaw people or chiefs marry with high-status women that kept the trade networks open, as it helps them to interact with traders over other groups.
Chickasaw had a matrilineal system, according to that children of the couple will have their right on the mother's clan, which helped them to expand their territory.
As mother and father were from two different tribes, children learn bilingual and make them able to understand other languages as well helped them to protect them from rival tribes.
Hence, the correct answer is "b, c, d."