Respuesta :
The best answer would be letter D. Walking on the treadmill is easy but the hard part is being consistent with your routine in order to maintain cardiovascular health. As Bethany goes on walking on the treadmill, the activity becomes familiar which leads to boredom. She needs to explore other physical activities so that excitement and the interest will still be there.
The correct answer is D) She can explore other types of physical activity to combat the tedium of her workout. From the explanation sentences it's clear that Bethany is bored. If you wish to exercise regularly, change is always needed, since, if you're just doing the same thing over and over again, it's bount to become tedious.