"wziąć" is perfective, so it's more like 'take' while 'brać' is more like 'be taking'.

Mateusz1898 is right that somehow both of these work here, but 'bierz' is more colloquial, true.

'Brać' and 'wziąć' both mean to take. Here I think 'bierz' sounds a bit more colloquial, but it really depends on the context.

"Na moją odpowiedzialność"