What type of insulation is primarily received at the Subsolar Point?

The Subsolar Point is the location on the Earth's surface where the Sun is directly overhead at solar noon, resulting in the most intense solar radiation received at that particular point. At this point, sunlight travels the shortest path through the atmosphere with minimal scattering or absorption, allowing for maximum energy to reach the surface.

Direct insulation specifically refers to solar radiation that arrives in a straight line from the Sun without significant alteration, such as scattering or reflection. This contrasts with other types of insulation, which involve the modification of sunlight before it reaches the surface. For instance, reflection involves solar energy bouncing off surfaces, while diffusion pertains to sunlight being scattered in different directions, which results in a reduction of the intensity of sunlight that reaches the ground.

Thus, at the Subsolar Point, because the Sun is at its zenith, the solar energy received is purely direct, making it the correct answer. This phenomenon is significant for understanding various climatic and environmental conditions associated with areas around the Equator and effects on weather patterns.