**Core Concept**
The question is testing the student's knowledge of targeted therapy in oncology, specifically the mechanism of action of certain tyrosine kinase inhibitors (TKIs) that target the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2).

**Why the Correct Answer is Right**
Trastuzumab (Herceptin) is a monoclonal antibody that binds to the extracellular domain of HER2, inhibiting its dimerization and subsequent activation of downstream signaling pathways, including those mediated by tyrosine kinase. Additionally, Trastuzumab can induce antibody-dependent cellular cytotoxicity (ADCC) and inhibit angiogenesis. Trastuzumab is used in the treatment of HER2-positive breast cancer.

**Why Each Wrong Option is Incorrect**
**Option A:** Lapatinib is a dual TKI that inhibits EGFR and HER2, but it is not the primary drug that acts by inhibiting tyrosine kinase activated by EGF receptor as well as HER2.
**Option B:** Gefitinib is a TKI that specifically inhibits EGFR tyrosine kinase, but it does not target HER2.
**Option C:** Imatinib is a TKI that specifically inhibits BCR-ABL tyrosine kinase in chronic myeloid leukemia (CML), but it does not target EGFR or HER2.

**Clinical Pearl / High-Yield Fact**
Trastuzumab is a monoclonal antibody that has revolutionized the treatment of HER2-positive breast cancer, demonstrating the importance of targeted therapy in oncology.

**Correct Answer:** C.