The following code tries to compute a result.

Where are variables 'a' and 'b'? explain

Dmains Startups AREA Test_Instructions, CODE, READONLY EXPORT main THUMB ALIGN ENTRY ; Mark first main PROC LDR R1, =a LDR R2, (R1] LDR R3, =b LDR R4, [R3] ADDS R5, R2, R4 LDR R6, =c STR R5, [R6] 15 stop B stop ENDP 20 AREA Test_Data, DATA, READONLY ALIGN 22 a DCD 2 23 b DCD 1 NNNNNNNNNM AREA Result_Data, DATA, READWRITE ALIGN 27 C SPACE O END Oo Dmains Startups AREA Test_Instructions, CODE, READONLY EXPORT main THUMB ALIGN ENTRY ; Mark first main PROC LDR R1, =a LDR R2, (R1] LDR R3, =b LDR R4, [R3] ADDS R5, R2, R4 LDR R6, =c STR R5, [R6] 15 stop B stop ENDP 20 AREA Test_Data, DATA, READONLY ALIGN 22 a DCD 2 23 b DCD 1 NNNNNNNNNM AREA Result_Data, DATA, READWRITE ALIGN 27 C SPACE O END Oo