**Core Concept**
Tram-line calcification, also known as tram-track calcification, refers to a specific pattern of calcification seen on radiographs, typically in the context of breast lesions or other conditions. This type of calcification appears as parallel, linear, or tram-track-like structures.

**Why the Correct Answer is Right**
Tram-line calcification is often associated with fibroadenomas, a type of benign breast tumor. The calcification is thought to result from the deposition of calcium within the fibrous stroma of the tumor, leading to the characteristic tram-track appearance. This type of calcification is relatively common in fibroadenomas and can be an important diagnostic feature on mammography.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not directly related to the characteristic pattern of calcification seen in fibroadenomas.
**Option B:** While calcifications can be seen in various breast conditions, tram-line calcification is not typically associated with ductal carcinoma in situ (DCIS).
**Option C:** This option is not a known association with tram-line calcification.

**Clinical Pearl / High-Yield Fact**
Fibroadenomas are the most common type of benign breast tumor, and tram-line calcification is a characteristic feature that can aid in their diagnosis on mammography. It's essential to recognize this pattern to avoid unnecessary biopsies and reassure patients with benign lesions.

**Correct Answer: C. Fibroadenoma.**