Which of the following lists contain only elements?
a. air, iron, iodine, magnesium.
b. zinc, gold, aluminium, oxygen.
c. nitrogen, copper, mercury, water.
d. chlorine, argon, sodium, limestone.

In which elements are belonging to? I will grant that option B ; ti's the best answer.
                 In which thou might contain the elements zinc , gold , aluminium , and last by not least oxygen.

I truly hope ti's answer helps thou. 

Hno3(aq) → h+(aq) + no3−(aq). picture ii best represents the strong acid hno3. strong acids are strong electrolytes

Outermost (valence) electrons