An entity reported the following events during 2018

It was decided to write off P800,000 of obsolete inventory

A counting error relating to the inventory on December 31, 2017 was discovered. This required a reduction in the carrying amount of inventory at that date of P300,000

Sales of P600,000 had been omitted from the financial statements for the year ended December 31, 2017.

The provision for uncollectible accounts receivable on December 31, 2017 was P300,000. During 2018, P500,000 was written off the December 31,2017 accounts receivable.

What pretax total amount should be reported as prior period errors in 2018?

a. P1,700,000

b. P1,100,000

c. P1,900,000

d. P900,000

please explain per bullet why is it should be reported as error in 2018 and why not.

thanks