Which preposition to use with explanatory

of Occurrences 60%

He is followed by another who chants in deep bass tones a legend explanatory of the virtues of the great saint of Baghdad.

to Occurrences 1%

But to the uninitiated he is explanatory to a scruple, as though mischief might ensue from his being misapprehended.

with Occurrences 1%

Then after a little pause, "She may prove rather more explanatory with you than she has been with me.

Which preposition to use with  explanatory