Final answer:
In the case of a patient hit in the arm with a baseball with resulting pain and discoloration, a focused exam (A) should be performed to assess the severity and provide appropriate care.
Step-by-step explanation:
The patient with a baseball injury to the arm and obvious black discoloration, indicating a bruise or contusion, calls for a focused exam (A). The evaluation should aim at assessing the affected area, checking for the severity of the injury, whether it's a sprain, fracture, or soft tissue injury, and determining what immediate care is needed. A rapid trauma exam would be more appropriate if there were multiple injuries or if the patient was in a more severe systemic state. Since the patient is alert, oriented, and the injury seems isolated to the left arm, a detailed assessment of that area is warranted. This assessment includes checking for any deformities, wounds, impaired circulation, or restricted range of motion. The healthcare provider should document the findings and manage pain appropriately, such as applying ice, immobilizing the joint if necessary, and considering over-the-counter pain relief or prescribing medication as indicated.