$4.$ All of Kola Company$$s sales are credit sales shipped free on board $($FOB$)$ shipping point. Kola typically records sales transactions $($that is$,$ sales and cost of sales$)$ throughout the year on the billing date. The internal auditor gathered the following information and documented it in his workpapers.

Invoice Number Date Shipped Date Billed

$835112/28/201912/29/2019$

$835212/29/20191/2/2020$

$83531/2/202012/31/2019$

$83541/2/20201/3/2020$

a$.$ Describe the specific audit procedures that should be performed to determine whether sales transactions occurring immediately before and after year$-$end are recorded in the proper period.

b$.$ Record the adjusting journal entries $($ignore dollar amounts$)$ the internal auditor should propose based on the cutoff information documented above. Include a clear and concise explanation for each proposed entry.