The expression "hog-wild" means ______.

A．pigs have remained unchanged for centuries
B．pigs are naturally vicious animals
C．pigs make a significant contribution to modem life
D．pigs are better than any other animal for laboratory

A．their social roles are rigidly determined
B．most boys would like to follow their fathers' professions
C．boys like to play with their fathers while girls with their mothers
D．they like challenging activities