How will bad AS grades impact my application?

I am currently studying 4 a-levels and completed my AS recently. Unfortunately, I got a, a, a, c 😱 for the four AS grades. I am aiming to get 3a*s, and my predicted grades are somehow 3a* 1a (how? lol).

While my grades do meet the entry requirements and the c subject is not required for the course I want to get into, will the AS grade impact my application in a very negative way?

Apparently UCAS will not allow me to put down only 3 subjects, so I will have to include my c AS. My application will definitely be worse than people with 4as, but will it be even worse than 3as? (Having a c on my application will definitely look very bad).

In addition, having a predicted grade of A for a subject with C AS may make the predicted grades (including other subjects) look unreliable.

What should I do now? Should I drop the subject and apply with only 3 (while still putting down the C), or should I apply with 4 and tell them on UCAS that I will retake the failed AS units?

I would appreciate some help here, thanks.