ANSWER
Vertical rays
Step-by-step explanation
We have two types of rays from the sun: vertical rays (direct sunlight), which are those rays that hit the surface of Earth vertically, and slanted rays (indirect sunlight), which are those that hit the surface with an angle less than 90° with the surface. We can appreciate both in the following diagram,
As is shown in the diagram, direct sunlight hits the surface in a smaller area than indirect sunlight. This way, the vertical rays are more concentrated than slanted rays and, therefore, give more heat - note that the energy provided by those rays will be concentrated in a smaller area.
Hence, vertical rays give more heat from the sun.