Km indicates enzyme-substrate affinity Steps:

• Km is the substrate concentration at half V_max; lower Km means higher affinity.
• Compare Km values: enzyme C has Km = 1.5 × 10^{-2} mol dm^{-3}, enzyme F has Km = 5.0 × 10^{-4} mol dm^{-3}.
• Enzyme F's Km is lower than C's, indicating greater affinity for its substrate.
• No data on enzyme P or V_max, so focus on given Km comparison.

Why C is correct:

• Lower Km reflects higher enzyme-substrate affinity, as per Michaelis-Menten kinetics, where Km inversely correlates with binding strength.

Why the others are wrong:

• A: No V_max data provided for any enzyme.
• B: Km does not determine time to reach V_max; that's influenced by enzyme concentration and substrate levels.
• D: No Km value given for enzyme P.

Final answer: C