Which of the following statements is INCORRECT?
A Symbols V, L, D can never be subtracted while writing roman numerals.
B Symbol I can be subtracted from V and X only once.
C Symbol X cannot be subtracted from L.
D None of these
A and C are incorrect
It says that X CANNOT be subtracted from L which is wrong as X - L is meaningful and forms XL (40). So (c) is the answer.