4 single bonds around a central atom would be 4 electron groups with zero lone pairs, which would yield a molecular shape of tetrahedral
Answer is: (Knowing the code allows you to understand the message)
Answer:
C) H⁺
Explanation:
When we are balancing the reaction<em> in an acid medium</em>, hydrogen is balanced using the <u>H⁺</u> species. This is most likely the intended answer of your question.
When the reaction takes place not in an acid medium, but in <em>an alkaline one</em>, then hydrogen is present as the OH⁻ species. However this option is not given in your question.
Thus the answer is option C).