## Core Concept
The question tests knowledge of bacterial morphology and classification, specifically focusing on Gram-negative cocci. Gram-negative bacteria have a thin peptidoglycan layer in their cell wall and an outer membrane containing lipopolysaccharides. Cocci are spherical or oval-shaped bacteria.

## Why the Correct Answer is Right
Neisseria gonorrhoeae and Neisseria meningitidis are both Gram-negative cocci. They are pathogenic bacteria that cause gonorrhea and meningitis, respectively. These bacteria are characterized by their diplococci arrangement, often seen as two adjacent cocci. This morphology and their Gram-negative staining are critical for their identification.

## Why Each Wrong Option is Incorrect
* **Option B: Bacillus** - This genus consists of Gram-positive, rod-shaped bacteria, not cocci or Gram-negative.
* **Option C: Staphylococcus** - While Staphylococcus species are cocci, they are Gram-positive, not Gram-negative.
* **Option D: Streptococcus** - This genus also consists of Gram-positive cocci, typically arranged in chains.

## Clinical Pearl / High-Yield Fact
A key point to remember is that Neisseria species (e.g., *N. gonorrhoeae* and *N. meningitidis*) are fastidious and require special media for growth, such as Thayer-Martin agar for *N. gonorrhoeae*. Both are significant pathogens that can cause severe diseases.

## Correct Answer: A.
a) Neisseria gonorrhoeae
e) Neisseria meningitidis