The correct option is D Microfilaments
During cytokinesis, a contractile ring of actin filaments forms at the equator between the two poles that will separate into two cells. The contractile ring is formed by the bundling of pre-existing microfilaments, or actin fibres, into the middle region. So in animal cytokinesis, cleavage occurs with the help of microfilaments.
Long protein fibres called microtubules extend from the centrioles in all possible directions, forming what is called a spindle. Some of the microtubules attach the poles to the chromosomes by connecting to protein complexes called kinetochores.
Microfibril is a fine fibril one of the submicroscopic elongated bundles of cellulose of a plant cell wall.