A dealer purchased a parcel of bank-accepted bills at a yield of 2.5% p.a., and sold the parcel a few weeks later at a yield of 3% p.a.; the dealer's holding-period yield (per annum) would be:

a.exactly 2.5%

b.exactly 3%

c.between 2.5% and 3%

d.less than 2.5%

e.more than 3%.