Which of the Following Statements Best Describes the Characteristics of Accumulating

Which of the following statements best describes the characteristics of accumulating physical capital and human capital?

A) Both physical capital accumulation and human capital accumulation are characterized by decreasing marginal returns.
B) Physical capital accumulation is subject to decreasing marginal returns, but human capital accumulation is not.
C) Human capital accumulation is subject to decreasing marginal returns, but physical capital accumulation is not.
D) Neither physical capital accumulation nor human capital accumulation is characterized by decreasing marginal returns.
E) Both physical capital accumulation and human capital accumulation are characterized by increasing marginal returns.