Answer:
The answer is "Primary Somatosensory Cortex".
Step-by-step explanation:
The sensations we experience such as touching something warm or cold, extending our muscles and limbs and changing their locations and orientations are collectively called somatic sensations and they are processed in the brain's "Primary Somatosensory Cortex". So the answer of the primary target area in the cortex of our brain for information of muscle stretch etc is the primary somatosensory cortex.
I hope this answer helps.