Answer :

Hello!

As we have the command DISPLAY (a) in the end, and a ← 3, it means that the variable a will receive the value 3.

After that, we have another attribution:

b ← 15, that means b will receive the value 15.

So, at this moment we have these values:

a = 3

b = 15

But now we have the last attribution:

the variable a will receive the value contained in b, expressed by a ← b, so the first value of a will be superscript by the value of b, resulting in:

a = 15

b = 15

So, the program will display the value of a, 15.