The following code tries to compute a result. Where are variables 'a' and 'b'? main.s Startup.s 600 van WNE AREA Test_Instructions, CODE, READONLY EXPORT main THUMB ALIGN ENTRY ; Mark first 10 11 12 13 14 main PROC LDR R1, -a LDR R2, (R1) LDR R3, 5b LDR R4, (R3] ADDS R5, R2, R4 LDR R6, =C STR R5, [R6] stop 16 B stop 17 ENDP 19 AREA Test Data, DATA, READONLY 21 ALIGN 22 a DCD 2 23 b DCD 1 18 20 24 25 26 27 28 AREA Result Data, DATA, READWRITE ALIGN C SPACE 0 29 END RAM ROM Port F O PLL