Which of the following categories are NOT a class of consumers?

Correct option is D

Correct option (d), Producers  

• Producers, also known as autotrophs, are organisms that produce their own food through the process of photosynthesis (in plants) or chemosynthesis (in some bacteria).
• Producers are at the base of the food chain in ecosystems and form the foundation for all other trophic levels (herbivores, carnivores, etc.).
  

Information booster : 

•   Parasites: Parasites are organisms that live on or inside another organism (called the host) and benefit at the host's expense. They derive nourishment and other benefits from the host, often causing harm or disease.
• Herbivores​ are animals that primarily feed on plants. They are one of the major types of consumers in the food chain, and they play a crucial role in the ecosystems by controlling plant populations and serving as prey for carnivores.
• Carnivores are animals that primarily consume other animals (meat). They are an essential part of the food chain, often acting as predators that help control the populations of herbivores and other species, thus maintaining the ecological balance.