Hi jinty, was on my phone earlier at work (tut tut).
My addition seems terse and abrupt (not intended)
my reasons are that 'Rate' has been included in the def, so would doubt very much that it would also be in the answer. Also that if it had been poorly put in place, the grammar would not fit as it would have to be rate(D), not rate.
Sorry if it came across abruptly. : )