Stephen's Ontime Delivery (SOD) is a delivery company. On January 1, 2018, one of its customers paid $8,400 in cash to SOD for services to be provided over the course of the year (until December 31, 2018). The amount of work SOD will do for the customer will be spread evenly throughout the year. The company has a monthly accounting period. On January 1, 2018, SOD recorded the following incorrect entry to account for the $8,400 payment Increase cash by 58.400 Increase revenue by $8.400 a) Has SOD overstated or understated revenue in January 20187 b) by how much has SOD overstated or understated revenue at January 31, 2018