Adverb. It’s modifying the “worked” not the “we”
Examples of sentences with the structure (not) as... as:
His face is not as round as Tom´s.
Her eyes are not as big as mine.
His nose is as turned-up as his mother´s.
Mary´s hair is as curly as her friend´s.
The policeman is as angry as the car driver.
The TV host is not as bored as the audience.
The children are as happy as their grandparents.
Answer:
B. They value Mrs. Hale's insights about Mr. Wright's "cheerfulness" and trust Mrs. Peters to obey the law.