Why are the saturated solutions of electrolytes for the salt bridge prepared in agar-agar jelly or gelatin?

• A. The jelly acts as an electrolyte
• B. It helps the electrolytes to mix with the contents of the half cells
• C. It helps maintain the electrical polarity between the two half-cell solutions
• D. It keeps the electrolyte in semi-solid phase and prevents it from mixing with the two half-cell solutions