Thanks a lot, probus. I came across this test question and suspected both A and B are OK for the blank:
Please send us all the information _______ you have about the candidate for the position.
A. that B. which C. as D. what
The given answer is A. I think the test question setters made a question like this according to the grammar rules like the following:
Martin Hewings' ADVANCED GRAMMAR IN USE:
We use that as subject after something and anything; words such as all, little, much, and none
used as nouns; and superlatives. (Which is also used as subject after something and anything, but
less commonly.) We use that or zero relative pronoun as object after these:
These walls are all that remain of the city, (not ...all which remain...)
She's one of the kindest people (that) I know, (not ...who I know.)
Is there anything (that) I can do to help? (rather than ...anything which I can do...)
Then can we conclude 'all +that clause' is OK (NOT: ALL WHICH...) but all the + noun that/which is OK too?