Beyond700, you're right that was a typing mistake. it should be "rate." sorry about that. i've corrected the mistake. and about your question regarding "capability to", option B will still be wrong. because you can't add a gerund right after "to". for example:
The capability to predicting= wrong
The capability to predict = correct because "to predict" is an infinitive. I've never seen a gerund that comes right after the word "to."
and guys, honestly, the best way to approach any SC question is this:
when you look at every answer choice, ALWAYS find a reason why it should be eliminated. if you can't, then keep it and look at the rest of the answer choices until you end up with either 2 or 3 answer choices. THEN compare them again and always try to find a reason to take one out until you eventually end up with the right answer. it's always easier to eliminate the wrong answers then to pick the right answer. the english language uses so much variation of correct grammar usage that i really doubt you can end up learning all the right grammar. however, creating wrong answer choices are sooo limited that they are much easier to spot. POE is really your best friend.