Coefficients in a chemical formula provide a) the relative numbers of products and reactants.
Explanation: Coefficients are the numbers placed in front of the reactants and products in a chemical equation. They indicate the proportion of each substance involved in the reaction. For example, in the reaction 2 H2 + O2 → 2 H2O, the coefficients show that two molecules of hydrogen react with one molecule of oxygen to produce two molecules of water. This representation helps to understand the stoichiometry of the reaction without implying an absolute quantity, making the coefficients essential for balancing equations and determining the proportions of reactants and products.