A golgi tendon organ responds to increases in muscle tension (option A).
The golgi tendon organ is a proprioceptor, sense organ that receives information from the tendon, that senses tension.
For instance, when one lift weights, the golgi tendon organ is the sense organ that tells how much tension the muscle is exerting.
This increase in muscle tension as a result of contraction of muscles is detected by the golgi tendon organ.