The muscle that acts to flex and adduct the arm from the options provided is d. coracobrachialis.
The coracobrachialis is located in the upper arm and is responsible for assisting with the flexion and adduction of the arm at the shoulder joint. It originates from the coracoid process of the scapula and inserts into the medial side of the humerus. This muscle plays a key role in positioning the arm closer to the body and raising it forward.
In contrast, the triceps brachii (option a) is primarily responsible for extension of the elbow, while the brachialis (option b) mainly flexes the elbow joint but does not perform adduction. The brachioradialis (option c) is involved in flexing the forearm at the elbow but also does not adduct the arm. Finally, the anconeus (option e) serves as an accessory muscle in elbow extension and has no significant role in flexing or adducting the arm.