Final answer:
The correct evaluation of dy/dt, when x and y are functions of t, is found by differentiating y with respect to t, which is exactly represented by option D) dy/dt.
Step-by-step explanation:
The student is asking how to evaluate dy/dt given that x and y are functions of t. To find the derivative of y with respect to t, denoted as dy/dt, one must look at the relationship between y and t. If y is explicitly given as a function of t, then dy/dt can be found using differentiation rules.
If y is given in terms of another function, the chain rule may be required. The provided options A) ∫x dt B) ∫y dt C) d(x)/dt + d(y)/dt suggest different mathematical operations, but only option D) dy/dt directly represents the derivative of y with respect to t.