An economy of 80 million people has ten percent of them engaged in research and development, where their productivity is 0.0035. The economy is on a balanced growth path, when suddenly 2.88 million people move from goods production into R&D, raising the fraction there to 13.6 percent. In the one period that begins with this labor reallocation, the growth rate of output is ________. [Refer to the instruction above.]

A) 2.8%

B) 0.0%

C) 3.8%

D) 2.2%

Please clearly explain it. Step by step. Thank you from the bottom of my heart.