If $R=\{(x,y):x,y\in Z,\ x^2+3y^2\leq8\}$ is a relation on the set of integers $Z$, then the domain $R^{–1}$ is :

(1) {–1, 0, 1}

(2) {–2, –1, 1, 2}

(3) {0, 1}

(4) {–2, –1, 0, 1, 2}

(1) {–1, 0, 1}

(2) {–2, –1, 1, 2}

(3) {0, 1}

(4) {–2, –1, 0, 1, 2}