On 1/9/2018 a company sells merchandise to another company, and the sale is made in a currency other than the sellers currency. The seller collects the amount on 1/2/2019, and converts it to its own currency on 1/3/2019. The total exchange gain or loss is related to the difference between the rates on which two dates (the seller prepares its financial statements on 31/12/2018):

1/9/2018 and 1/3/2019

1/9/2018 and 1/2/2019

31/12/2018 and 1/2/2019

1/2/2019 and 1/3/2019

31/12/2018 and 1/3/2019