The correct option is B Agar agar
Imbibition is the process of absorbing water by the solid particles without forming a solution. Agar agar is the solidifying agent that are used to form solid culture media. It is also called as powerful imbibant as it absorbs 99% more water than its weight and proteins absorb 15% then comes the cellulose the weakest imbibant. Thus, the correct answer is option A.