Hello everyone!
I've got a question regarding the position of adverbs such as 'retrospectively' with respect to an infinitive construction, e.g.:
a) It is possible to retrospectively evaluate the procedures that...
b) It is possible to evaluate retrospectively the procedures that...
c) It is possible to evaluate the procedures that ... retrospectively.
d) It is retrospectively possible to evaluate the procedures that...
Which of the above is correct? Some of them appear more natural to me than others and some even seem to have a slightly different meaning.
Being a non-native, however, I'm not sure (admittedly, it's been a long day here and my the countdown for a general restart of my cognitive functions has already begun).
Sorry if this quesiton has been answered before. I'll be grateful for any advice!

P.