Step 1: Understand oxidizing property.
An oxidizing agent gains electrons and gets reduced itself.
Greater electronegativity and electron affinity generally increase oxidizing power.
Step 2: Compare the given elements.
Fluorine is the strongest oxidizing agent because of:
(i) very high electronegativity
and
(ii) very high reduction potential
Thus,
\[
F
\]
has maximum oxidizing property.
Oxygen is also a strong oxidizing agent but weaker than fluorine.
Chlorine has high oxidizing ability, but less than oxygen and fluorine.
Nitrogen has the least oxidizing character among the given elements.
Step 3: Arrange in decreasing order.
Therefore, the correct decreasing order of oxidizing property is
\[
F \gt O \gt Cl \gt N
\]
Step 4: Final conclusion.
Hence, the correct answer is
\[
\boxed{F \gt O \gt Cl \gt N}
\]