The Correct option is E. Chemical energy to Mechanical energy.
When two element combine to form more than one compound i hope this helps you with work have a nice day :)
The number of neutrons is variable, resulting in isotopes, which are different forms of the same atom that vary only in the number of neutrons they possess. Together, the number of protons and the number of neutrons determine an element's mass number.
tbh google
hope it helps
