Answer: d. none of the other answers
Explanation:
Enzymes that turn chemical energy into mechanical work are molecular motors.
There are three main components of cytoskeleton including microtubules, actin filaments and Intermediate filaments. Only actin filaments and microtubules carry the motor-driven transport on the cytoskeleton.
The most important feature of intermediate filaments is to provide the plasma membrane with mechanical support where it comes into contact with the extracellular matrix and other cells.
Unlike microtubules and microfilament , intermediate filaments are not involved in motility of the cells, hence do not associat with molecular motors.
Hence, the correct option is d.