The predicate of the sentence is?
A. Jacob and Ruth?
B. Boot of the taxi?
C. Jacob and Ruth piled up their entire luggage?
D. Piled their entire luggage into the Boot of the taxi?

The predicate of the sentence is? A. Jacob and Ruth? B. Boot of the taxi? C. Jacob and Ruth piled up their entire luggage? D. Piled their entire luggage into the Boot of the taxi?