"One of the" or "an"?

1. I turned on the screen and it presented me a bunch of options. I clicked on one of the options to turn off the entire system.

In the above sentence does "one of the options" imply that there were multiple options to turn off the system or was there just one and I clicked that one of the options?

2. I turned on the screen and it presented me a bunch of options. I clicked on an option to turn off the entire system.

Here I used "an option", can I use this if I know that the listener doesn't know that there was an option to turn off the system? So I used "an option". Is this correct even if there was only one option to turn off the system?

1. I clicked on one of the options to turn off the entire system.

This does suggest there were several options to switch the system off.

There are several ways to rewrite it.

I clicked on the option to turn off the entire system.

I clicked on one of the options: to switch off the entire system.

Or, if the system was successfully turned off, you could say,

I clicked on one of the options and turned off the entire system.

Your second idea repeats "option" and sounds awkward.