According to the passage......
a. cleaning birds by hand was not effective
b. the Elf oil company releases oil off Holland
c. ships releases oil to get rid of annoying birds
d.most birds die after being washed in the machine
Compared to cleaning birds by hand, the main advantage of Elf's machine is that it.....
a. costs less per oiled bird
b. helps to reduce sea pollution
c. saves time when time is short
d. makes the birds much cleaner