**Core Concept**
Atropine is an anticholinergic medication that blocks the action of the neurotransmitter acetylcholine at muscarinic receptors in the central and peripheral nervous system. This leads to its therapeutic effects, such as reducing salivation and bronchial secretions, but also its side effects and contraindications.

**Why the Correct Answer is Right**
Atropine is contraindicated in glaucoma because it can cause mydriasis (pupil dilation) and increase intraocular pressure, which can exacerbate glaucoma. This is due to the blockade of muscarinic receptors in the eye, leading to unopposed alpha-adrenergic receptor stimulation and subsequent vasoconstriction of the episcleral vessels. The resulting increase in intraocular pressure can cause further damage to the optic nerve.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect because atropine is not contraindicated in angle-closure glaucoma; in fact, it is sometimes used to treat this condition by dilating the pupils to help open the angle.

**Option B:** This option is incorrect because atropine can actually be used to treat gastrointestinal motility disorders such as peptic ulcer disease, where it helps to reduce gastric acid secretion and promote healing.

**Option C:** This option is incorrect because atropine is not contraindicated in hyperthyroidism; in fact, it is sometimes used to help manage symptoms such as tremors and tachycardia.

**Clinical Pearl / High-Yield Fact**
When using anticholinergic medications like atropine, it's essential to be aware of their potential to exacerbate conditions like glaucoma, and to monitor patients for signs of increased intraocular pressure.

**Correct Answer:** D. Glaucoma