A cab driver is taking a small child passenger (age 3) to daycare (the mother had an early morning meeting to attend and booked the ride for her child and paid by credit card over the phone). The child is injured when it opens the door to the cab and falls out during the ride. There are no child proof locks on this particular cab. Which aspect of negligence law is the key issue here? (1point)

	Standard of care
	Voluntary assumption of risk
	Causation
	Damages