**Core Concept**
Breast cancer is a common malignancy with well-established risk factors including age, genetics, reproductive history, and family history. It arises from ductal or lobular epithelial cells, and its presentation varies by subtype. Paget’s disease is a rare variant often associated with underlying ductal carcinoma.

**Why the Correct Answer is Right**
Option D is incorrect because prolonged breastfeeding is actually **protective** against breast cancer, not a risk factor. Long-term breastfeeding is associated with a reduced risk due to reduced lifetime exposure to estrogen and improved breast tissue differentiation. In contrast, older age, nulliparity, and family history (e.g., affected sibling) are established risk factors. Paget’s disease is typically linked to **intraductal** carcinoma, making option B accurate.

**Why Each Wrong Option is Incorrect**
Option A: Affected sibling is a risk factor — This is true; shared genetics and environment increase risk.
Option B: Paget’s disease of nipple is intraductal type of CA — This is true; it often arises from intraductal carcinoma and is a variant of ductal carcinoma.
Option C: Common in aged nulliparous — True; nulliparity and older age are well-known risk factors for breast cancer.

**Clinical Pearl / High-Yield Fact**
Prolonged breastfeeding is associated with a **lower** risk of breast cancer, not increased incidence. This is a key exam trap — students often confuse protective factors with risk factors.

✓ Correct Answer: D. Increased incidence with prolonged breast feeding