Assertion: Interstitial cell is present in the region outside the seminiferous tubule called interstitial spaces.
Reason:: Interstitial cells provide nutrition to the sertoli cells.

Assertion (A) is true but Reason (R) is not correct.

The regions outside the seminiferous tubules called interstitial  spaces, contain small blood vessels and interstitial cells or Leydig cells. Sertoli cells provide nutrition to the germ cells .