Two expressions each represent the sale price of the item are:
Expression B : 0.8p is correct
Expression D: p - 0.2p is correct
<em><u>Solution:</u></em>
The regular price of an item at a store is p dollars
The item is on sale for 20% off the regular price
Therefore,
Regular price = p dollars
Discount = 20 % of regular price
Therefore,
Discount = 20 % of p

Sale price = Regular price - discount price
Sale price = p - 0.2p
Thus Expression D: p - 0.2p is correct
On solving, sale price = p - 0.2p
Sale price = 0.8p
Thus expression B : 0.8p is correct