Question: "If compound X is boiling, then its temperature must be at least 150?C." Assuming that this statement is true, which of the following must also be true?
a. If the temperature of compound X is at least 150?C, then compound X is boiling.
b. If the temperature of compound X is less than 150?C, then compound X is not boiling.
c. Compound X will boil only if its temperature is at least 150?C.
d. If compound X is not boiling, then its temperature is less than 150?C.
e. A necessary condition for compound X to boil is that its temperature be at least 150?C.
f. A sufficient condition for compound X to boil is that its temperature be at least 150?C.