16. Suppose a Colleague's app you encounter: compare(greenFrog, RedFrog); Which is most likely being used:

a. Comparable

b. Comparable

c. Comparator

d. Comparator

e. both a & b

f. both c & d

17. Which is a valid way to compare two frog objects, refernced by frog1 and frog2?

a. frog1.compare(frog2)

b. frog1.compareTo(frog2)

c. frog1.compare(frog2)

d. frog1.compareTo(frog2)

e.both a & b

f. both c & d

20. to enhance app security, we keep private _______ variables hidden from external access.

a. static

b. protected

c. package

d. constant

e. abstract

f. refrence