Well informed about (4)
I believe the answer is:
upon
(Other definitions for upon that I've seen before include "Onto" , "Abreast of, au fait with" , "Thereafter" , "Carried - on top" , "Preposition" .)
I believe the answer is:
upon
(Other definitions for upon that I've seen before include "Onto" , "Abreast of, au fait with" , "Thereafter" , "Carried - on top" , "Preposition" .)