Help with a few questions.

Which of the following is a molecule but not a compound ?
A.Sodium Chloride (I know that’s not the answer)
B.Fructose
C.Nitrogen gas
D.Hydrochloric acid

2.Which of the following is a trace elements?
A. Silicone
B.Phosphorus
C.Sulfur (my answer)
D.Magnesium
E.Potassium

3.Which of the following is the least electronegative?
A. Copper
B. Rubidium
C. Fluorine
D. Selenium

4. Entropy is
A. Part of the 1st law of thermodynamics
B. Disorder
C. Part of the 2nd law of thermodynamics.
D. A and B
E. B and C (my answer)