Final answer:
a) Myosins are the motor proteins that interact with actin by walking along microfilaments, specifically F-actin filaments. Hence, option a) is correct.
Step-by-step explanation:
The motor proteins that interact with actin are myosins. Myosin is a motor protein that walks along microfilaments, specifically F-actin filaments.
These motor proteins use the free energy from ATP hydrolysis to undergo conformational changes and enable movement.