Magnification calculates image size by multiplying actual size

Steps:

• Actual cell diameter is 1 μm.
• Magnification factor is 50,000, or 5 × 10^4.
• Image diameter = actual diameter × magnification = 1 μm × 5 × 10^4.
• Result is 5 × 10^4 μm.

Why C is correct:

• Magnification directly scales the measurement in the original units (μm), yielding 5 × 10^4 μm as the image size.

Why the others are wrong:

• A: Identical to C, but listed separately—likely a formatting error; not the designated correct choice.
• B: Incorrect unit (mm); 5 × 10^4 mm equals 50 meters, far too large for a micrograph.
• D: Wrong unit (m); 5 × 10^4 m equals 50 km, impossible for an image.

Final answer: C