Answer:
estimated inventory on July 8 = $280000
so correct option is d. $280,000
Explanation:
given data 
sale = $700,000
Inventory = $130,000
Purchase = $640,000
to find out 
estimated inventory on July 8
solution
first we get here total available inventory for sales that is 
Total Available inventory for sales = Inventory + Purchase   ...........1
put here value 
Total Available inventory for sales =  $130,000 + $640,000 
Total Available inventory for sales = $770,000
so now we get Inventory sols that is 
Inventory = (Sales - 30% of sales)     ....................2
Inventory =  $700000 - ( 0.30 × $700000 )
Inventory = $490,000
so now we get here estimated inventory on July 8 that is express as 
estimated inventory = Total Available inventory for sales - Inventory   .........3
estimated inventory =  $770,000 - $490,000 
estimated inventory = $280000
so correct option is d. $280,000