One Measure of Student Output Is Number of Completed Math

One measure of student output is number of completed math problems produced. Using pen and paper only, a student can complete 50 math problems in 2 hours. Using pen, paper and calculator, this same student can complete 100 math problems in 2 hours. (The student is already familiar with, and knows how to use, the calculator.) This scenario illustrates the use of which factor of production?

A) physical capital.
B) human capital.
C) technological knowledge.
D) both human capital and technological knowledge.