Which function is represented by the graph above ?

a: f (x) = { -x - 3, x less than equal to 0
{ 1/2x + 1, x > 0

b: f (x) = { x - 3, x less than equal to 0
{ -1/2x + 1, x > 0

c: f (x) = {-x + 3, x less than equal to 0
{ 1/2x + 1, x > 0

d: f (x) = { x + 3, x less than equal to 0
{ - 1/2x + 1, x > 0