Step 1: Understand the assertion.
Cochlear implants are indeed effective in helping children with hearing impairments. They can restore some hearing ability by providing auditory signals to the brain.
Step 2: Evaluate the reason.
While cochlear implants do amplify sound, their primary function is not just amplification but providing auditory input by bypassing damaged parts of the ear and directly stimulating the auditory nerve.
Step 3: Conclude.
Both assertion and reason are true, but the reason does not fully explain why cochlear implants are effective.
Step 4: Final Answer.
The correct answer is B.