Answer: c. +4
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here manganese is having an oxidation state of +4 called as cation and oxygen forms an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged to give 
which written in simplest whole number ratios to give neutral 
An increase in kinetic energy corresponds to an increase in temperature. Out of boiling, condensation, freezing, and precipitation, boiling is the only one that indicates an increase in temperature.
1. <em>Increasing the concentration of one or more reactants will often increase the rate of reaction. This occurs because a higher concentration of a reactant will lead to more collisions of that reactant in a specific time period. </em>
<em>2. Physical state of the reactants and surface area.</em>
The correct answer is a Photon.
One photon is released for each event. Photons are elementary particles of all electromagnetic radiation, including light.
I think it is b..................................................
