can you give me the fully explanation, thx.

65. A pension fund that begins with $500,000 earns 15% the rst year and 10% the second year. At the beginning of the second year, the sponsor contributes another $300,000. The dollar-weighted and time-weighted rates of return, respectively, were A. 11.7% and 12.5%. B. 12.1% and 12.5%. C. 12.5% and 11.7%. D. 12.5% and 12.1%