#csp

Question 1: Single choice

Five squares of a board must be colored red (R) or black (B) so that squares sharing a side differ. The constraints are 1–2, 2–3, 1–4, 2–5 and 4–5 (squares 1, 2, 3 form the top row and 4, 5 sit under 1 and 2). All domains are {R, B}. You assign 1 = R and run forward checking. What are the domains of squares 2, 3, 4, 5 afterwards?

2 = {B}, 3 = {R}, 4 = {B}, 5 = {R}1
2 = {B}, 3 = {B}, 4 = {B}, 5 = {B}2
2 = {B}, 3 = {R, B}, 4 = {B}, 5 = {R, B}3
2 = {R, B}, 3 = {R, B}, 4 = {R, B}, 5 = {R, B}4

Timed test