**Core Concept**
Non-typable Haemophilus influenzae (NTHi) is a bacterium that lacks the polysaccharide capsule, which is the primary virulence factor of typical H. influenzae. As a result, NTHi can cause a range of infections, primarily affecting the respiratory tract and the eyes.

**Why the Correct Answer is Right**
Non-typable H. influenzae can cause otitis media, sinusitis, and conjunctivitis due to its ability to adhere to and colonize the mucosal surfaces of these organs. The bacterium's adherence to epithelial cells is mediated by its surface proteins, such as the outer membrane protein P2 (OMP P2). This adherence allows NTHi to evade the host's immune response and establish a persistent infection.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because NTHi can cause invasive diseases, such as meningitis, epiglottitis, and pneumonia, particularly in individuals with compromised immune systems or underlying conditions.
* **Option B:** Incorrect because NTHi is a common cause of otitis media, a condition characterized by inflammation of the middle ear.
* **Option C:** Incorrect because NTHi can cause conjunctivitis, a condition characterized by inflammation of the conjunctiva, the membrane covering the white part of the eye and the inside of the eyelids.

**Clinical Pearl / High-Yield Fact**
NTHi is a leading cause of otitis media in children, and its treatment often involves the use of antibiotics such as amoxicillin-clavulanate or azithromycin.

**Correct Answer:** A.