When you apply, you're authorizing the creditor to pull 1, 2 or 3 bureaus. However many they feel they "need" to pull to approve you is what you are allowing them to pull.
Capital One almost always does all 3. I have definitely heard of Amex doing 2 or 3 for more borderline cases. However, there is no point in speculating over what they will pull for you. The only real way to know is to apply and see what happens.
