I would say at night, when it's cooler. At night, desert temperature lowers due to the lack of water. Deserts cannot support much vegetation, so at night the sand loses all of its heat, making it colder. Sand is a major reason why deserts are hot.
The correct statement is:
All sedimentary rocks contain weathered rock and sediment.
Sedimentary rocks are formed by material that has been removed from other rocks by weathering and which has been deposited in the place and became a rock by the process called sedimentation .
B would be the false statement