Different body cells can respond differently to the same peptide hormones because
a. different target cells have different sets of genesb. the hormone is chemically altered in different ways as it travels through the circulatory systemc. the circulatory system regulates responses to hormones by routing the hormones to specific targetsd. a target cell's response is determined by the components of its signal transduction pathways

D. a target cell's response is determined by the components of its signal transduction pathways

Explanation:

Signal transduction pathway is a set of steps from the ligand binding (e.g. hormone binds to its receptor) to the cell response. The chain reaction that occurs after the ligand binding can include mechanisms such as phosphorylation, dephosphorilation, activation of messengers, degradation etc which together can make a whole huge network.

The cell response at molecular level can include change in gene expression (changes in transcription and translation), protein changes (conformational, post-translational modifications, change in location).