If I think it's a potential customer, I'll answer it.
I'll tell them 'Sorry I can't speak at the moment, I'm up a ladder, I'll call you back'. Mostly, it works a treat, it stops them 'dead in conversation' and they are happy I will call them back.
If It's a sales call and I fancy some fun, I say the same thing 'Yes I am the business owner, but I'm working UP A LADDER at the moment. 99% of calls will say 'oh sorry, I'll call back'. A few have just carried on with their speech, I just hang up.
Mostly, if it's not a local number, I can't even be bothered to answer; if it's important they will leave a message on the voicemail.