A:Mike, have you finished your homework yet?
B:Of course, I've finished!
Im studying *social studies
I studied for three hours in the morning and
now.
started studying at 1:30 in the afternoon.
A:Good! So you've studied ( ) today.
(注) social studies 社会科
(ア for three hours イ
for four hours ウ for five hours エ for six hours)