We have written the following LC-3 program that computes 4(a+b+c+d). As the program shows, variables a,b,c and d have been assigned in different memory locations with their initial values set in lines 20 to 23 . The final result of that expression (function) is stored in memory location Label_2. However, there are some missing instructions in lines 4, 8, 14, and 16. 2 a) Add the missing LC-3 ISA instructions for these missing lines and explain why they should be added there. (10 points) b) What value will be stored in Label_2 after execution of the program? Give this value in hexadecimal representation (base-16). (5 points)