How many 10-bit strings are there subject to each of the following restrictions? (a) no restrictions. (b) the string starts with 001. (c) the string starts with 001 or 10. (d) the first two bits are the same as the last two bits. (e) the string has exactly six 0's. (f) the string has exactly six 0's and the first bit is 1. (g) there is exactly one 1 in the first half and exactly three 1's in the second half.