Answer:
A hypothesis is a basically a theory proposed to a subject or refrence to an act with limited evidences.
The meaning of inference is the process of inferring something and it is a noun
The answer is D. As the ambulance gets closer, the sound waves are compressed relative to the person; so the frequency increases.
The resonant frequency of a circuit is the frequency
at which the equivalent impedance of a circuit is purely real (the imaginary part is null).
Mathematically this frequency is described as

Where
L = Inductance
C = Capacitance
Our values are given as


Replacing we have,



From this relationship we can also appreciate that the resonance frequency infers the maximum related transfer in the system and that therefore given an input a maximum output is obtained.
For this particular case, the smaller the capacitance and inductance values, the higher the frequency obtained is likely to be.