Mollusks like clams and snails have a simple heart that pumps through open-ended vessels.
blood
water
hemolymph
lymphocytes

Ans.

Mollusks are organisms of an invertebrate phylum mollusca. In these organisms, open circulatory system is present, in which a fluid-filled cavity (hemocoel) bathes different body organs to provide nutrients and oxygen.

Mollusks show a three-chambered, simple heart with two auricles and a single ventricle. The ventricle pumps hemolymph into the aorta, which is then transferred to the rest of the body organs.

Thus, the correct answer is option). 'hemolymph.'