Final answer:
The adverb form of 'defective' is 'defectively'. It is the word that accurately modifies verbs, adjectives, or other adverbs to indicate manner, degree, or circumstance related to the adjective 'defective'.
Step-by-step explanation:
The adverb form of "defective" is defectively. Among the options provided, choice (b) Defectively is the correct transformation of the adjective "defective" into an adverb.
Adverbs modify verbs, adjectives, or other adverbs, often indicating the manner, degree, or circumstance of the action or quality described.
For example, in the sentence "The device was functioning defectively," the adverb 'defectively' indicates the manner in which the device was functioning.