31. MARK valid C variable names VALID and invalid C variable names INVALID. For invalid C variable names, EXPLAIN WHY they are invalid. (Note that valid means acceptable to the compiler, rather than good programming practice.) (a) number_of_students in CS1313 (b) number of students in CS1313 (c) 2_to_tango (d) WHAZZAT (e) Huh? 3 32. For each of the following, WRITE A DECLARATION STATEMENT for a variable rep- resenting this quantity. For each, you should choose an appropriate data type. The name should comply with the "favorite professor" rule, and should also be a valid C identifier. You DON'T need to initialize the variables. Assume that int variables and float variables take 4 bytes (32 bits) each. (a) the number of students in CS1313 (b) your height in lightyears (a lightyear is the distance that light travels in a year, which is about 6 trillion miles). (c) a spaceship's speed in inches per century, approximated to three significant figures (as- sume that the spaceship travels at 99% of the speed of light) (d) the number of players on a team