The correct answer is c) Write the complete balanced chemical equation.
Stoichiometry is the branch of chemistry that deals with the calculation of the quantities of reactants and products involved in a chemical reaction. A balanced chemical equation is necessary for stoichiometric calculations because it shows the mole ratio between reactants and products. Without a balanced chemical equation, it is impossible to determine the correct mole ratios and perform accurate stoichiometric calculations.
Option a) and b) are not relevant to stoichiometric calculations, as they pertain to nuclear chemistry, not chemical reactions. Option d) is related to the concept of Avogadro's number, which is important for calculating the number of atoms or molecules in a given amount of substance, but it is not directly related to stoichiometry.