Final answer:
The statement is best supported by option b. Exothermic reaction. When hydrogen peroxide decomposes, heat is released, producing large amounts of steam.
Step-by-step explanation:
The statement that heat is given off and large amounts of steam are produced when hydrogen peroxide decomposes is best supported by option b. Exothermic reaction. In an exothermic reaction, heat is released to the surroundings, resulting in an increase in temperature. When hydrogen peroxide decomposes, it releases heat and forms water and oxygen gas, which can condense as steam in the presence of moisture.