Answer:
d.class
Step-by-step explanation:
All living organisms were grouped into a system of classification comprising of 7 levels i.e. Kingdom, Phylum/Division, Class, Order, Family, Genus, and Species. Organisms grouped into the same level of classification has something in common.
In this question, a snake, frog or toad are different species of organisms. They all belong to the same Kingdom, which is Animalia. Snakes, toads and frogs are also commonly grouped into the Phylum Chordata because they all possess a backbone.
However, the next level of classification, which is CLASS, is the first to differentiate the snake from a toad or frog. Snakes belong to the class: Reptilia while toads and frogs belong to the class: Amphibia i.e. animals that can live on both land and water.