If 2(a^2+b^2)=(a+b)^2 then,

If $2(a^2+b^2)=(a+b)^2$

Then put the value of a and b = 1

$2(1^2+1^2)=(1+1)^2$

= 4 = 4

So satisfy from the options by putting the value of a and b = 1

If we choose a = b this will satisfy the equation.