Which muscle raises the upper arm?

The deltoid muscle is primarily responsible for raising the upper arm. It is a large, triangular muscle located on the shoulder, and its main function is to facilitate various movements of the shoulder joint, including the abduction (lifting away) of the arm. Specifically, the deltoid muscle allows for lifting the upper arm in various directions, making it essential for many activities such as lifting, reaching, and throwing.

The other choices do not pertain to the movement of the upper arm. The upper leg and lower leg involve muscles that control movements of the leg and do not engage the upper arm. The lower arm, or forearm, contains muscles that are primarily responsible for movements of the wrist and hand, rather than the shoulder or upper arm. Thus, the deltoid muscle is the only relevant option for the action of raising the upper arm.