Malacology is the study of
a. Shells
b. Molluscs
c. Muscles
d. Mammals

Hint: It is the second-largest phylum, including about 23% of all the named marine organisms. Abundant members of this also live in freshwater and terrestrial habitats. They are highly varied, not just in size and anatomical structure, but also in actions and habitat.

Complete answer:
Malacology is the division of invertebrate zoology that deals with the study of the Mollusca (mollusks or mollusks), the second-major phylum of animals in terms of described species after the arthropods. Mollusks involve snails and slugs, clams, octopuses and squid, and many other kinds, most of which have shells. Archaeology utilizes malacology to get aware of the evolution of the climate, the biota of the area, and the usage of the site.

Fields within malacological research comprise classification, ecology, and evolution. Applied malacology studies medicinal, veterinary, and farming applications, such as mollusks as vectors of disease, as in schistosomiasis.

The study of molluscs shells is known as conchology. The study of muscles is called Myology. Mammalogy is the learning of mammals.

Hence, the correct answer is option (B).

Note: In malacology, it is disclosed that most molluscs have eyes, and all have sensors to sense chemicals, vibrations, and feel. The simplest type of molluscan reproductive system relies on external fertilization, but more compound variations occur. The three most universal characteristics defining recent molluscs are a mantle with a major cavity used for breathing and excretion, the existence of a radula (except for bivalves), and the structure of the nervous system. Other than these common elements, molluscs articulate great morphological range.