Answer:
A. Is challenging but still allows for proper form
Step-by-step explanation:
To increase the strength in weight training one should opt for weights that are not too heavy but is challenging enough to hit the number of reps that one set for themselves.
Too heavy weight might affect one’s proper form and one might end up hurting oneself. The best weight is the one that make you struggle to achieve your set goals and you want to take rest before there are few reps left.