Which of the following is a sign of an improperly fitted car seat?

An improperly fitted car seat can be identified by the fact that it can be moved with little effort. A correctly installed car seat should be securely anchored to the vehicle, with minimal movement. An installation that allows the seat to shift or rotate easily indicates that it is not tightened properly, which can compromise the safety of the child in the event of a crash.

When a car seat is secure, it should not move more than an inch in any direction when pulled at the base. This stability is critical for providing effective protection during a collision, as a properly fitted seat absorbs the forces of an impact and keeps the child restrained.

The other choices refer to different signs of improper fitting but may not directly indicate the seat's security in its installation, such as harness adjustments or placement, which do play critical roles in overall safety but are not singular indicators of the seat's stability in the car.