If I had to guess, I would say B, though it could also be D. I'd bet on B the most.
- Aerobics physical activity is any of various sustained exercises<span>, as jogging, rowing, swimming, or cycling, that stimulate and strengthen the heart and lungs, thereby improving the body's utilization of oxygen.
- Anaerobic physical activity is </span><span>a </span>physical exercise<span> intense enough to cause lactate to form.</span>
