Answer:
B
Explanation:
A discrete function is one which has points rather than continuous lines when it is graphed.
o o o o o o o is a discreet function.
The function given is not discreet. Every n value after n has been defined above or equal to 20 is continuous. You could argue that what about numbers below 20. They don't have values associated with them. But after the restriction is obeyed, the function has no holes.
if you let g(n) = y and substitute y for the left side of the function, you get
y = (3/5)n - 12) that's much more familiar or should be, so the function is continuous and linear.
The answer is B.