A firm has the production function f(x, y) = y + min{x, y}. The isoquants for the firm if x is on the horizontal axis:

a) are L-shaped with the corners of the L's on the line y = x.

b) are L-shaped with the corners of the L's on the line y = x + 1.

c) consist of two line segments, one vertical and the other with a slope of 1

d) consist of two line segments, one horizontal and the other with a slope of 1.