From an Isoquant Map One Can Illustrate Diminishing Returns to Production

From an isoquant map one can illustrate diminishing returns to production by

A) Observing the slope of the isoquant as one moves outward on the labor axis but stays at the same point on the capital axis
B) Following the curvature of an individual isoquant
C) Moving from isoquant to isoquant along a ray from the origin
D) Constructing a positively sloped isoquant