4 Nano Bhd's production and sales records for the period 2011-2014 are summarized below: Units produced Sales Unit RM Unit RM 2011 300,000 150,000 250,000 200,000 2012 330,000 180,000 300,000 280,000 2013 320,000 170,000 280,000 320,000 All units produced from 2011 until 2013 are assigned using weighted average cost. Required: (a) Calculate the gross profit for each year, assuming that inventory values are calculated using (i) FIFO method, and (ii) LIFO method. (b) According to MFRS 102 Inventories, which method is not acceptable for the valuation of inventory and why?