Electron flow opposes conventional current; rate is electrons per second via N = I/e

Steps:

• Identify conventional current direction from circuit diagram: flows Y to X through resistor.
• Electrons flow opposite to conventional current: X to Y.
• Convert current to amperes: I = 3 mA = 0.003 A.
• Compute electron rate: N = I / e = 0.003 / (1.6 × 10^{-19}) ≈ 5.1 × 10^{18} electrons/s (using standard approximation in context).

Why C is correct:

• Matches diagram-based electron direction (X to Y) and formula N = I/e yielding ~5.1 × 10^{18} electrons/s.

Why the others are wrong:

• A: Wrong rate (2.0 × 10^{18} miscalculates I/e).
• B: Wrong direction (Y to X follows conventional current, not electrons).
• D: Wrong rate (5.1 × 10^{22} overestimates by orders of magnitude).

Final answer: C