Which of these transactions would produce $10,000 of expenses in December? (check all that apply)

a)BOC buys $10,000 of copper in December.

b)BOC uses copper to make batteries at a total cost of $10,000 in December.

c)BOC sells batteries costing $8,000 in December for $10,000 cash.

d)BOC sells batteries costing $10,000 in December for $12,000 cash.

e)BOC signs a contract in December to buy $10,000 of copper.