A 65-year-old female presents with progressive fatigue, shortness of breath, and numbness and tingling in her feet. Blood work reveals macrocytic anemia, and her serum vitamin B12 level is low. Which of the following is the most appropriate initial treatment?

✓ Correct Answer: Option B

The patient has symptoms and lab findings consistent with vitamin B12 deficiency, including neurological symptoms. Due to potential malabsorption (common cause), intramuscular vitamin B12 is the preferred initial treatment to ensure adequate repletion and prevent irreversible neurological damage.