Ralp h i s a plumber . Whic h o f th e followin g ar e include d i n hi s huma n capital?
A.
th e knowledg e h e learne d o n th e job , an d th e tool s h e uses
B.
th e knowledg e h e learne d o n th e job , bu t no t th e tool s h e uses
C.
th e tool s h e uses , bu t no t th e knowledg e h e learne d o n th e job
D.
neithe r th e knowledg e h e learne d o n th e jo b no r th e tool s h e uses