What is wrong with the following while loop?

while ( sum <= 1000 )
sum = sum – 30;

a. The parentheses should be braces.
b. Braces are required around sum = sum – 30;.
c. There should be a semicolon after while ( sum <= 1000 ).
d. sum = sum – 30 should be sum = sum + 30 or else the loop may never end.

d. sum = sum – 30 should be sum = sum + 30 or else the loop may never end.