**Core Concept**
Insulin-like growth factor 1 (IGF-1) is a protein hormone that plays a crucial role in regulating cell growth, differentiation, and survival. It exerts its effects by binding to its specific receptor, which is a member of the receptor tyrosine kinase family.

**Why the Correct Answer is Right**
IGF-1 binds to the IGF-1 receptor (IGF1R), a transmembrane receptor with intrinsic tyrosine kinase activity. Upon binding, IGF-1 induces dimerization of the receptor, leading to the activation of its intrinsic tyrosine kinase activity. This results in the phosphorylation of tyrosine residues on the receptor and its substrates, initiating a cascade of signaling events that regulate cell growth, survival, and metabolism. The IGF1R signaling pathway is involved in various physiological processes, including embryonic development, tissue repair, and glucose homeostasis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the insulin receptor (INSR) is a different receptor that is activated by insulin, not IGF-1.
**Option B:** This option is incorrect because the epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is activated by epidermal growth factor (EGF), not IGF-1.
**Option C:** This option is incorrect because the platelet-derived growth factor receptor (PDGFR) is a receptor tyrosine kinase that is activated by platelet-derived growth factor (PDGF), not IGF-1.
**Option D:** This option is incorrect because the fibroblast growth factor receptor (FGFR) is a receptor tyrosine kinase that is activated by fibroblast growth factor (FGF), not IGF-1.

**Clinical Pearl / High-Yield Fact**
IGF-1 signaling plays a crucial role in the regulation of glucose metabolism, and its dysregulation has been implicated in various metabolic disorders, including insulin resistance and type 2 diabetes.

**Correct Answer: C. IGF-1 receptor (IGF1R)**