In the code fragment below, what is the state of the registers R4, R5, and R6 after the code fragment is executed (all numbers decimal unless otherwise specified)?

mov R0, #18

mov R1, #17

add R4, R0, R0

add R5, R1, R1

sub R6, R5, R4

R4 = 36 R5 = 34 R6 = 2

R4 = 36 R5 = 34 R6 = -2

R4 = 18 R5 = 17 R6 = 1

R4 = 17 R5 = 18 R6 = -1