The diagram in figure 3 shows the design of an n-bit adder using n one-bit adders, where n = 32 in the diagram. the carry-out of bit-i is the carry-in of bit i+1, where carry-in of bit 0 is 0. the procedure should have three parameters: a, b, and n, where a and b are two lists representing two inputs numbers, and n is the length of a and b: (n-bit-adder a b n). two solutions are acceptable: follow the design in figure 3, and follow the binary addition algorithm given in the lecture slides. in both case, you must call at one of the procedures that you defined in question 2.

3.1 define a procedure (tail lst), which returns the last element of lst. (4 points)

3.2 define a procedure (rmtail lst), which returns the list without the last element of lst. (4 points)

3.3 follow the fantastic-four abstract approach to design your recursive solution by explaining: (1) what is the size-n problem of your procedure? (2) what are the stopping condition and its return value? (3) what is the size-(n-1) problem? what are the steps to construct the size-n problem solution from the size-(n-1) solution. write the answers as comments in the program. (4 points)