Using the digits 0 through 9, find out how many 4-digit numbers can be
configured based on the stated conditions:
a. [1 pt] The number cannot start with zero and no digits can be repeated.
b. [1 pt] The number must begin and end with an odd digit. (Repeated digits are
okay.)
c. [1 pt] The number must be at least 5000 and be divisible by 10.(Repeated
digits are okay.)
d. [2 pt] The number must be less than 3000 and must