Which two public methods must be implemented in a functional custom shipping method directly extending Mage_Shipping_Model_Carrier_Abstract and also implementing Mage_Shipping_Model_Carrier_Interface? (Choose two)
A. collectRates()
B. getAllowedMethods()
C. isTrackingAvailable()
D. isFixed()
E. getConfigData()
F. checkAvailableShipCountries()