b. endocrine
Paracrine cells are the ones that secrete a sign directly to its neighbors, to the extra cell space and not to the blood.
Endocrine cells are the ones that secrete a hormone to the blood system to be distributed to some specific place in the body.
The autocrine system is the release of a hormone from the cell to that same cell.
The exocrine glands are those who release a specific type of hormone or enzyme to some part of the body, through canals.
