Only the first option, it's hard to podnieść=pick up liquid from the floor ;) I guess this sentence was supposed to have this possible humorous interpretation. A bar of soap is "kostka mydła", so here - kostkę mydła.
The latter will probably be "On wyciera/zmywa mydło z podłogi" (wyciera - the floor is being made dry; zmywa - the floor is being made clean).
This gets into the idiosyncrasies between the language. How one would express a concept in different languages is frequently entirely different. Some of these translations are hard to get right without any visual context at all.
Take for example this simple one: PL: Ile masz lat? EN (literal): How many years do you have? EN (correct interpretation): How old are you?
If you asked an American with no foreign language experience (because, in Spanish, for example, the same sentence is 'quantos anos tienes', which is exactly the same form as PL), 'How many years do you have?' They would look at you quizzically and assume you might be referring to years of professional experience.
In some cases "z=with", but not in general. Prepositions do not translate that easily between languages even when everything else does.
- ze mną - with me
- (śmiejesz się) ze mnie - (you are laughing) out of me
- z Polski - from Poland
- (większość) z nich - (the majority) of them
- Zabierz nogi ze stołu - Take your feet off the table.
and that's not a complete list.