This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to repair vertical blinds
Adjust blinds that won't turn.
If your blinds aren't closing, or if one or two won't close, this is usually a simple fix. Check each blind individually.

Pick from:
[I] It's likely one or two blinds are backwards and simply need to be twisted into the right position. Blinds may also be overlapping, in which case you can use your hands to gently push them apart.;
[II] If they don't catch on to their position, you may have to do some work to loosen the screws or bolts holding them in place. The first time you replace blinds you may find that they snap over time.;
[III] If they won't shut, loosen any weak or unfixable screws holding them in place. If they aren't working, that's a sign of a storm moving in, or shutters are falling.;
[IV] Consider replacing smaller blinds that will close more easily. Smaller blinds tend to go worse the longer they stay open, so when you place them over windows, or try moving them outside, they might go much worse.;
The answer is:
[I]