Answer:
A) Na
Explanation:
We analyze the change of electrons in the equation.
So:
S (0) --> S (-2)
The oxidizing agent is the one that gains electrons. Sulfur goes from 0 to -2 then it is gaining electrons.
Na (0) --> Na (+1)
The reducing agent is the one that loses electrons. Sodium goes from 0 to +1 which means that it loses electrons.
Therefore the reducing agent is Na.
