Which set is a basis for P2P_2P2 (polynomials of degree ≤2\leq 2≤2)?
{1,1+x,1+x+x2} \text{\{} 1, 1+x, 1+x+x^2 \text{\} }{1,1+x,1+x+x2}
{1,x,2x} \text{\{} 1, x, 2x \text{\} }{1,x,2x}
{1,x2} \text{\{} 1, x^2 \text{\} }{1,x2}
{x,x2,x3} \text{\{} x, x^2, x^3 \text{\} }{x,x2,x3}