Answer:
Gross profit ratio= 20; inventory turnover ratio= 4.00.
Step-by-step explanation:
Given option in the question are incorrect for gross profit ratio as option given are for Inventory turnover ratio.
Given: Net sales= $420000.
 Cost of goods sold= $336000
 Gross profit= $84000
Now, claculating the gross profit ratio.
Formula; Gross profit ratio= 

⇒ Gross profit ratio= 

∴ Gross profit ratio= 20
Now, finding the Inventory turn over ratio.
Formula; 

Average inventory= 

⇒ Average inventory= 

∴ Average inventory= 

Next, 

⇒ 

Hence, Gross profit is 20 and inventory turnover ratio is 4.00