**Core Concept**
The underlying principle being tested is the interpretation of hysterosalpingography (HSG) findings in the context of infertility. HSG is a diagnostic tool used to assess the shape and structure of the uterus and fallopian tubes. **Fallopian tube abnormalities** can be a significant cause of infertility.

**Why the Correct Answer is Right**
The description of 'bead-like' fallopian tubes and clubbing of the ampulla is suggestive of **salpingitis isthmica nodosa (SIN)**, a condition characterized by nodular thickening of the fallopian tube, often associated with infertility. This condition can lead to tubal damage and infertility due to the formation of diverticula and adhesions.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not match the description provided.
**Option B:** Similarly, this option does not align with the 'bead-like' appearance and clubbing of the ampulla.
**Option C:** This option is also incorrect as it does not correspond to the specific HSG findings mentioned.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that **salpingitis isthmica nodosa (SIN)** is a common cause of infertility and can be diagnosed through HSG. The 'bead-like' appearance of the fallopian tubes is a classic finding in SIN.

**Correct Answer:** D. Salpingitis isthmica nodosa.