How does one determine they are the "lower option"?
You can't always determine it obviously but there are tell tale signs that are obvious to the seasoned daters and maybe not so obvious to others just starting out.
For example, I look at texting response rate and habits. If you just texted and held a convo with a gal and all of a sudden she goes cold, you can pretty much bet she has a more interesting option she's texting with.
If you ask her on a date and she cancels last minute with any bs excuse, you can bet she's going out with the better option.
If you ask her when she's free and she's wishy washy about her schedule, you can bet she has other options lined up in the pipeline and is keeping you as a backup.
If you're always initiating texting her even though you made it clear that you are interested in her and she never initiates the text, you're not her first option.
If after a first date, she's late to respond to your text, she's looking at better options.
Etc...