The sentence that was capitalized correctly is <span>B. My easiest classes are Chemistry and Spanish.</span> Note that proper nouns or those that refer to specific names, things, or places should be capitalized. In this case, Chemistry and Spanish both refer to specific subjects taught in school.
Think of some of the highlights and not so great moments of your life. Also try to write it in chronological order from when they took place. I havent lived your life so I cant really give you examples.