Hafers, Inc. raises calves to sell. Hafers breeds its cows in April, and the cows calve in February of the following year. In January, Angus Inc. contracts with Hafers to buy fifty calves. Identification takes place in
a. January, when the contract is signed.
b.April, when the calves are conceived.
c.February, when the calves are born.
d.a reasonable period of time.