What kind of reaction involves the transfer of electrons?

The correct answer is indeed a redox reaction, which stands for reduction-oxidation reaction. In these types of reactions, there is a transfer of electrons between reactants. This transfer is a fundamental aspect of the reaction mechanism, and it involves one species losing electrons (oxidation) while another species gains electrons (reduction).

In a redox reaction, the oxidation state of the elements changes as electrons are exchanged. For example, when iron rusts, it combines with oxygen and water, leading to oxygen being reduced and iron being oxidized, illustrating the electron transfer process.

Other types of reactions mentioned, like synthesis and decomposition, do not inherently involve a transfer of electrons. A synthesis reaction involves combining two or more substances to form a new compound, while a decomposition reaction breaks down a compound into simpler products without electron transfer. Combustion reactions often involve redox processes but are specifically characterized by the reaction of a fuel with oxygen to produce heat and light, which also implies electron transfer. However, since redox reactions encompass the broader concept of electron transfer, it is the most precise answer for this question.