**Core Concept**
Kusumlata's presentation is consistent with acute angle-closure glaucoma, a medical emergency characterized by sudden onset of severe eye pain, redness, and elevated intraocular pressure. This condition occurs when the iris suddenly blocks the drainage system of the eye, leading to a rapid increase in intraocular pressure.

**Why the Correct Answer is Right**
Acute angle-closure glaucoma is typically caused by pupillary block, where the iris is pushed forward, blocking the trabecular meshwork and preventing aqueous humor from draining. The resulting increase in intraocular pressure can lead to corneal edema, optic nerve damage, and vision loss if not promptly treated. The characteristic vertically oval pupil is due to the iris being pushed forward, causing the pupil to become irregularly shaped.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the clinical presentation of acute angle-closure glaucoma.
**Option B:** This option is incorrect because it does not account for the pupillary block mechanism that leads to acute angle-closure glaucoma.
**Option C:** This option is incorrect because it does not match the typical clinical presentation of acute angle-closure glaucoma.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of acute angle-closure glaucoma is the presence of a mid-dilated pupil that is often vertically oval in shape. This is due to the iris being pushed forward, causing the pupil to become irregularly shaped.

**Correct Answer: C. Acute angle-closure glaucoma.**