Find out how many bags of rice have been shipped in or shipped out within two days:

a) Day one, 250 bags have been shipped in; Day two, 150 bags have been shipped out.

b)Day one, 100 bags have been shipped out; Day two, 120 bags have been shipped out.

c)Day one, 180 bags have been shipped out; Day two, 140 bags have been shipped in.

d)Day one, 175 bags have been shipped in; Day two, 175 bags have been shipped in.