Trista is trying to decide how to spend her money. She adds and subtracts by a dollar to determine which combination of expenses will offer her the greatest benefit. TristaÍs decision making process is an example of which of the following?

i. thinking on the margin
ii. analyzing costs and consequences
iii. economizing her decision
A.
i only
B.
i and iii only
C.
ii and iii only
D.
i, ii, and iii