Which link between two elements could you remove from the relation so that it becomes a function?

a) 2 and d or 5 and d
b) 2 and d or 3 and b
c) 3 and b or 3 and e
d) 3 and b or 4 and b

The figure shows triangle def and line segment bc, which is parallel to ef: triangle def has a point b on side de and point c on side df. the line bc is parallel to the line ef. part a: is triangle def similar to triangle dbc? explain using what you know about triangle similarity. part b: which line segment on triangle dbc corresponds to line segment ef? explain your answer. part c: which angle on triangle dbc corresponds to angle f? explain your answer. asap