Which rebar size corresponds to 0.38 lbs/ft?

The size of rebar is determined by its diameter, which is closely tied to its weight per unit length. In the rebar sizing system, each size is denoted by a number that correlates to its nominal diameter in eighths of an inch.

A rebar size of #3 corresponds to a diameter of 3/8 inches. The weight for #3 rebar is approximately 0.38 pounds per foot, which matches the weight specified in the question.

Therefore, identifying the correct rebar size relies on understanding the relationship between the size designation and its weight per foot. In this case, the calculation confirming that #3 weighs 0.38 lbs/ft supports why this option is the correct choice for the question. Other rebar sizes like #5, #7, and #8 would have higher weights per foot, making them unsuitable answers for this specific weight criterion.