Multi-choice problem: Choose from the options at the end, and answer how do you do this: How do I ensure the mold is sealed when making a concrete countertop?

OPT: (a). You'll need to properly seal the mold using a screwdriver. You want the caulk to have extra clean edges.; (b). You'll need to properly seal the mold using silicone caulk. You want the caulk to have extra clean edges.;
(b).