Please provide explanation aswell. thanks!

3. During September, a firm's inventory account included the following transactions: September 1 Inventory 25 units@$4.00 September 14 Purchased 60 units@$4.20 September 20 Sold 40 units@$6.00 September 21 Purchased 30 units @ $4.25 September 25 Sold 40 units @$6.10 Assuming periodic FIFO inventory costing, gross profit for September was: A $132 B. $147 C. $153 D. $160 4. Pears PLC adheres to IFRS. It recently imported inventory for $100 million, paid import tax of $ 2milion, carrying in cost of $5 million and spent $5 million for storage prior to selling the goods. The amount it charged to inventory expense ($ millions) was closest to: A $100 B. $105 C. $107 D. $115