The functions have to have the same value at -3 to be continues
A
(x^2 -9)/x+3 = ( x-3)(x+3)/ (x+3) = x-3 = -3-3 = -6
at x=-3 it is -6 so this function is continuous
B
(x^2 -9)/x+3 = ( x-3)(x+3)/ (x+3) = x-3 = -3-3 = -6
at x = -3 the function is 0
The values are not the same so this is not continuous
C
( x^2 +6x+9) / (x+3) = ( x+3) (x+3) / (x+3) = x+3 -3+3 = 0
at x = -3 the value is 9 so this is not continuous
D
( x^2 +6x+9) / (x+3) = ( x+3) (x+3) / (x+3) = x+3 -3+3 = 0
at x = -3 the value is 0 so this is continuous