**Core Concept**
Mammography involves the use of X-rays to produce detailed images of the breast tissue, allowing for early detection of breast cancer. The element used as the target material in mammography is crucial for producing the characteristic X-ray spectrum that distinguishes mammography from other medical imaging modalities.

**Why the Correct Answer is Right**
The element used as the target material in mammography is Molybdenum (Mo). Molybdenum has a high atomic number, which allows it to produce X-rays with a characteristic energy spectrum that is well-suited for mammography. The X-rays produced by molybdenum targets have a lower energy level compared to other target materials, making them more effective for imaging the dense breast tissue.

**Why Each Wrong Option is Incorrect**
**Option A:** Tungsten (W) - While tungsten is commonly used in mammography tubes, it is not the primary target material. Tungsten produces X-rays with a higher energy level, making it less suitable for mammography.
**Option B:** Copper (Cu) - Copper is not typically used as a target material in mammography. Its characteristic X-ray spectrum is not well-suited for breast imaging.
**Option C:** Silver (Ag) - Silver is not commonly used as a target material in mammography. Its X-ray production is not as efficient as molybdenum or tungsten.

**Clinical Pearl / High-Yield Fact**
Molybdenum targets are often used in combination with a molybdenum filter to further optimize the X-ray spectrum for mammography.

**Correct Answer: C. Molybdenum. Molybdenum is used as the target material in mammography.**