I would say B.
A, umm, don't crash trains, that's bad.
C, Lillian is wondering how fast a train can go, not at what curve will it fall.
D, Lillian isn't wondering about the size of the trains, just the speed.
Please provide a picture or a statement so we know the context!!
Answer:
Hey i think there is an error in ur question, u may recheck the so called word "metopus"
But here is the definition of Endosymbionts are organisms that form a symbiotic relationship with another cell or organism