Answer:
C. Talk test
Explanation:
The talk test would be readily available to me at the the least cost.
The talk test is about the easiest way that one can monitor intensity as they exercise. Because the only thing needed here is the ability to talk and to breathe.
The intensity lies on if one can talk and breathe at the same time. The harder one exercises, the more breathless they become and they find it difficult to talk.
