Agarose is a polymer composed of which of the following monomer(s)?

The correct option is C D-galactose and 3,6-anhydro-L-galactopyranose
Agarose gel is the solidified gel which serves as the matrix with definite pore size in gel electrophoresis. It is obtained by dissolving agarose powder in a buffer. Agarose is a polysaccharide extracted from certain red seaweeds. It is composed of repeating units of agarobiose. Agarobiose is composed of two different monomers: D-galactose and 3,6-anhydro-L-galactopyranose.
The cross linkage between these monomers creates pores in the agarose gel. The size of the pore depends on the degree of cross-linkage which is determined by the concentration of agarose. The pores present in the agarose gel creates a sieving effect that helps to separate DNA molecules under an electric field.