Answer:
B. Conserved
Step-by-step explanation:
Mechanical energy is equal to the sum of potential energy and kinetic energy of an object:
where U is the potential energy and K the kinetic energy.
When there are no resistive forces such as friction or air resistance, the mechanical energy of the object is conserved. As a result, the energy in such situation is converted from potential energy into kinetic energy (or viceversa). An example of this application is the free fall of an object: when the object is initially released from the top of a building, it has potential energy (U) but not kinetic energy since it starts from rest; as it falls down, all this potential energy is converted into kinetic energy (K), because its speed increases, and the total energy (E) is conserved.