Answer: Option D."Proteins"
Step-by-step explanation:
Cilia and flagella are defined as the projections from the cell which are made up of the motor protein naming dynein and microtubules.
Cilia and flagella contain 9 filaments that includes a complete microtubule, a partial microtubule,cross-bridges of the motor protein (dynein), and a pair of single microtubules.
Cilia and flagella performs two basic functions on the basis of movement of liquid on the surface of the cell, it enables single cells to swim in the cell and moves liquid over the surface for anchored cells in a tissue.
Hence, the correct option is proteins.