Microscope magnification is eyepiece times objective.

Steps:

• Calculate total magnification for each option by multiplying eyepiece and objective values.
• Option A: 5 × 100 = 500×.
• Option B: 10 × 40 = 400×.
• Option C: 15 × 40 = 600×.
• Option D: 15 × 100 = 1500×.

Why D is correct:

• Total magnification equals eyepiece magnification × objective magnification; 15 × 100 = 1500×, the highest value.

Why the others are wrong:

• A: 5 × 100 = 500×, lower than 1500×.
• B: 10 × 40 = 400×, the lowest total.
• C: 15 × 40 = 600×, less than 1500× due to weaker objective.

Final answer: D