Which one of the following is the correct pairing of a body part and the kind of muscle tissue that moves it?

The iris contains circular and radial smooth muscle fibres that change the size of the pupil; they are not under the control of the will. So 'iris – involuntary smooth muscle' is correct.
The heart wall is made of cardiac muscle, which is involuntary but striated.
The biceps of the upper arm is a skeletal muscle: striated and voluntary.
The muscles of the abdominal wall are also skeletal (striated, voluntary) muscles.
Hence the correct pairing is iris – involuntary smooth muscle.