- 4 friends purchased 7 items
- 7 items = 4 tops + 3 pillowcase
- each item are different integers
- every top is more expensive than the pillowcase
- the total price of the 7 items = $89

Target question => What was the price in dollars of the most expensive pillowcase?
Average = 89/7 = 12.7, no price of item can be $12.7 since the price are integers and $12 is not an exact average because 12 * 7 = 84 and not 89 and 13 * 7 = 91 which is now greater than 89
For an average price of $12, another $5 must be spent to get a total of $89
Therefore, the price of each item will be gotten from a sequence of 7 prices with $12 as the average

Statement 1 => The most expensive top cost $16
At an average of 12, the sequence of 7 items is $9, $10, $11, $12, $13, $14, $15. By adding $5 to the items in the sequence to produce different integers/price, have an average of $12 have the highest/most expensive top to be $16 and the total item to be 89.
$1 can be added to every item in the sequences starting from the highest/expensive item to spread the $5. So the prices are $9, $10, $12, $13, $14, $15, $16
The price of the most expensive pillowcase is $12. Statement 1 is SUFFICIENT

Statement 2 => The least expensive pillowcase cost $9
At an average of 12 the sequence of 7 it is $9, $10, $11, $12, $13, $14, $15. By adding $5 to the items in the sequence to produce different integers/price, have an average of $12, have the least expensive pillowcase to be $9 and total item to be 89, $1 can be added to every item in the sequence starting from the most expensive item to spread the $5, so the prices are $9, $10, $12, $13, $14, $15, $16
The price of the most expensive pillowcase is $12 but if the $5 was added to the expensive item alone, the 7 prices will be $9, $10, $11, $12, $13, $14, $20, and price of the most expensive pillow is not definite. Statement 2 is NOT SUFFICIENT

Since only statement 1 is SUFFICIENT,
Answer = A