both present with issues. When a selector is written in the form,
it denotes an HTML element node. HTML elements are themselves known as selectors, though not referred to as such in most instances. Ultimately, it would imply that such an element exists in the HTML language. P, DIV, UL, LI, &c. are all element nodes that are recognized in the DOM.
Happy are not.
It's also a general rule that selectors are not capitalized, so
Happy would be better written as,
happy. We still need to address the fact that they are not HTML elements. The exercise will have asked for either a class or an id and as the title suggests, it is ID. So your selectors, then, will be written with a hash, to denote an id attribute in the DOM.