10) C

People with high income spend more time on non-leisure travel than people with low income.
(Please note that the word ‘cannot’ change the meaning of the question entirely)

Option A is a plausible explanation. If people on lower incomes are less likely to have a car, they are more likely to spend less time on non-leisure travel.

Option B is a plausible explanation. If people on lower incomes do not commute to work so often, they are more likely to spend less time on non-leisure travel.

Option C is not a plausible explanation. If people on lower incomes use public transport, they would still be spending time on non-leisure travel. It does not matter whether they are driving or using public transport.

Option D is a plausible explanation. If the lower income group includes students who spend little time on transport, they are more likely to spend less time on non-leisure travel.

So option C is the correct answer.