MDC represents a perfect SAT score in Roman as perfect score on the SAT is 1600.
Roman numerals is an ancient Roman numeral system. This system use a combination of letters from the Latin alphabet to denote numbers.
They are made up of seven Latin letters. From bottom to top: I is for 1, V is for 5, X is for 10, L is for 50, C is for 100, D is for 500, and M is for 1,000.
The highest score in the SAT is 1600. To convert 1,600 into Roman Numerals you need to divide it into local values and then add them all to get the MDC.