Sensation, perception, generalization, and discrimination are the four stages of concept formation. These stages help individuals understand and categorize information in their environment. The correct order is:

d) Sensation, perception, generalization, and discrimination

Here is a detailed explanation of each stage:

1. Sensation:
Sensation is the first stage in the process of concept formation. It involves the initial gathering of information through our senses. Our sensory organs receive stimuli from the environment, such as visual, auditory, or tactile stimuli. For example, when we see an apple, our eyes detect the visual stimuli of its color, shape, and size.

2. Perception:
Perception is the next stage, where the sensory information is interpreted and organized by the brain. It involves making sense of the sensory input and assigning meaning to it. In the example of the apple, perception involves recognizing it as a familiar object and associating it with previous knowledge or experiences.

3. Generalization:
Generalization is the process of applying what has been learned from specific instances to broader categories or concepts. It involves identifying common features or characteristics among different stimuli and grouping them together. For example, after seeing and perceiving several different kinds of fruits, we can generalize the concept of "fruit" and understand that it refers to a category of edible objects with similar characteristics.

4. Discrimination:
Discrimination is the final stage of concept formation. It involves the ability to differentiate between stimuli and recognize their unique features or differences. Discrimination helps in identifying specific instances within a broader category. For example, within the concept of "fruit," discrimination allows us to distinguish between an apple, orange, or banana based on their distinct features.

In summary, concept formation involves the stages of sensation (gathering sensory information), perception (interpreting and organizing the information), generalization (grouping similar stimuli into broader concepts), and discrimination (recognizing and differentiating between specific instances within a concept). These stages help individuals make sense of their environment and categorize information effectively.