Clausius, a German physicist, made significant contributions to the field of thermodynamics. He formulated the first and second laws of thermodynamics, which play a fundamental role in understanding the behavior of energy and entropy in systems. The correct answer to the question is option 'C' - both of the mentioned laws are summarized by Clausius. Let's explore these laws in detail:

First Law of Thermodynamics:
The first law of thermodynamics, also known as the law of energy conservation, states that the total energy of an isolated system remains constant. Energy can neither be created nor destroyed; it can only be transferred or converted from one form to another. This law is often expressed using the equation:

ΔU = Q - W

Where ΔU is the change in internal energy of the system, Q is the heat added to the system, and W is the work done by the system. This law asserts that the total energy of a system is conserved, and any changes in energy are due to heat transfer or work done.

Second Law of Thermodynamics:
The second law of thermodynamics introduces the concept of entropy. Entropy is a measure of the randomness or disorder in a system. The second law can be summarized in two statements:

1. The total entropy of an isolated system tends to increase over time.
2. Heat cannot spontaneously flow from a colder body to a hotter body.

The first statement implies that natural processes tend to move towards a state of maximum entropy or disorder. It means that systems left to themselves tend to become more disordered over time. This behavior is often referred to as the "arrow of time" or the "irreversibility of natural processes."

The second statement, known as the Kelvin-Planck statement, sets a limitation on the efficiency of heat engines. It states that it is impossible to construct a heat engine that operates in a cycle and extracts heat from a single reservoir to produce an equivalent amount of work. Some energy is always lost as waste heat during the process.

Conclusion:
In summary, Clausius summarized the first law of thermodynamics as the conservation of energy and the second law as the tendency of entropy to increase in an isolated system. Both of these laws are fundamental to understanding the behavior of energy and entropy and have wide-ranging applications in various scientific and engineering fields.