Number one a and b are automatically out if you decrease the pitch or frequency you wont hear it louder it does not add up ok?
number 2 the answer would be C the higher the frequency the higher the pitch the lower the frequency the lower the pitch this just comes back to common sense. for example you cant decrease the frequency and than expect a louder pitch its like saying I am going to smash the key on this piano with all my strength and it will make a small very low pitch sound you get what I mean so your answer would indeed be C.
<span>When temperature is increased,
the rate of dissolving increases. The kinetic energy of the molecules of the
solute and solvent molecules is high thereby increasing their contact. An example
is mixing powdered sugar to the water. When you add water to the sugar, the
dissolving process is slow. However, when you increase the temperature of the
water by boiling it, the sugar dissolves immediately. </span>
C) volume and temperature.