Final answer:
If total product is increasing at an increasing rate, the marginal product is positive and increasing. This reflects increased efficiency and increasing returns at early production stages.
Step-by-step explanation:
When total product is increasing at an increasing rate, this means that each additional unit of input is producing more output than the previous unit, which implies that marginal product is increasing. Therefore, the correct answer is: A. positive and increasing. This occurs during the early stages of production when resources are being used more efficiently and there are increasing returns to scale.