A inputs a real number, subtracts 100, then outputs the square root of the result if it is real.
B inputs a date, then outputs the name of a person born on that date.
C inputs a real number x, then outputs a real number y that is less than 1/1000 larger than x.
D inputs a real number x, then outputs the result of the calculation x^2-1/(x-1)(x+1).
E inputs a real number x, then a coin is flipped. If the coin flips heads, the output is x+2. If the coin flips tails, the output is x+3.
F inputs a person, then outputs their birth date.
Which of these are functions. If there are more than one then seperate them by commas like B, C, D.