A small boy who is brought to the emergency department by his parents is found to have a spiral fracture of the femur, with a variety of ecchymoses. What is the most likely cause of the injuries –
The fracture can occur in all the four options given in questions.
But, a variety of ecchymoses suggests child abuse -

"Bruises are the most common manifestation of child abuse and may be found on anybody surface".
Automobile hit – and – run accident
Fall from a tree
Child abuse
Fall from a bicycle