A callable nested function add$\_$memory$\_$values as shown below calls another function $($plot$\_$function with parameter a$0)$ and being a nested function, it also gets called from somewhere. We assume that the code that follows uses the RISC$-$V calling conventions. We also assume that the function knows essentially nothing about its caller, nor about the function that it calls, i$.$e$.$ plot$\_$numbers $($that is other than knowing what parameters are passed returned. Assume that mv s$1,$ s$2$ is the pseudo instruction equivalent of: addi s$1,$ s$2,0,$ in other words, it copies register s$2$ to s$1.$

add$\_$memory$\_$values: # adds and plots numbers in array of integers

# SAVE REG$\_$SET$1$ ON STACK CODE GOES HERE

mv s$1,$ a$0$ # param with address of array of integers

mv s$2,$ a$1$ # parameter with number of integers to be added

# s$2$ will be used as a down counter

li t$2,0$ # initializes an accumulator

loop$1$:

lwu t$1,0($s$1)$ # load from integer array

add s$1,4$ # go to to next word for each time around loop

add t$2,$ t$1$ # add memory value to accumulator

mv a$0,$ t$2$ # parameter for plot$\_$numbers

# SAVE REG$\_$SET$2$ ON STACK CODE GOES HERE.

jal plot$\_$numbers # Call plot$\_$numbers

# RESTORE REG$\_$SET$2$ CODE GOES HERE

addi s$2,-1$ # decrement counter

bgtz s$2,$ loop$1$ # Loop until all numbers added

mv a$0,$ t$2$ # Return accumulated value in a$0$

# RESTORE REG$\_$SET$1$ CODE GOES HERE

ret

Given this, mark ALL of the statements that are true.

Group of answer choices

a$0$ and a$1$ should be saved because add$\_$memory$\_$values is a CALLER

REG$\_$SET$1$ should include ALL s# register found in RISCV because this function is a CALLEE

REG$\_$SET$1$ should include ra$,$ s$1,$ s$2$

Some t# registers will need to be saved for the program to be guaranteed to work.

ALL RISCV s# registers should be saved given that the function is also a CALLEE

t$1$ needs to be saved

plot$\_$numbers, being a leaf function should make use of as many s# registers as possible.

Any t# registers that need to be saved and restored are part of REG$\_$SET$2$

t$2$ needs to be saved

A leaf function is considered a CALLEE

t$1$ and t$2$ must be both saved because they are being modified by the function.