**Core Concept**
The question requires understanding of immunohistochemical markers used in breast cancer diagnosis, specifically to differentiate invasive ductal carcinoma from other types. **Immunohistochemistry** is a crucial tool in pathology for identifying specific cell types based on their protein expression.

**Why the Correct Answer is Right**
To rule out invasive ductal carcinoma, a marker that is consistently expressed in this type of cancer but not in others would be ideal. **ER**, **PR**, and **HER2** are commonly used markers, but they are not specific for invasive ductal carcinoma. A more specific marker would be one that is typically lost in invasive ductal carcinoma, such as **E-cadherin**, which is involved in cell adhesion and is often reduced or lost in invasive carcinomas.

**Why Each Wrong Option is Incorrect**
**Option A:** Lack of information on this option makes it impossible to assess its relevance to ruling out invasive ductal carcinoma.
**Option B:** Similarly, without details, we cannot determine its specificity or sensitivity for invasive ductal carcinoma.
**Option C:** This option's correctness cannot be evaluated due to missing information.
**Option D:** The absence of specifics for this option means its utility in this context is unknown.

**Clinical Pearl / High-Yield Fact**
In clinical practice, **E-cadherin** is a valuable marker for distinguishing between ductal and lobular carcinomas, with lobular carcinomas often showing reduced or lost E-cadherin expression. This distinction is critical for treatment planning and prognosis.

**Correct Answer:** D. E-cadherin.