<prompt> C- peptide is secreted by -A cellsB cellsD cellsF cells  <response>: Ans. is b i.e., B cells o Insulin is a polypeptide hormone which is synthesized as a larger preprohormone preproinsulin.o Asthepreprohormone enters the endoplasmic reticulum, 23 amino-acid signal peptide is removed and it is converted to prohormone proinsulin.o Proinsulin is made up A and B chain connected by a connecting peptide C-peptide or C-chain.o C-peptide is detached in the granules before secretion. Normally, 90-97 of the product released from B cells is insulin along with equimolar amounts of C-peptide.o Insulin is a two chain polypeptide having 51 aminoacids: The A chain has 21 while B-chain has 30-aminoacids.o Half life of insulin is about 5 minutes. 