A retail company's gross profit margin was 30% for the year 2018 and 38% for the year 2019. Which of the following could explain the change?

(1) The company sold their goods to customers at a higher price in 2019 than in 2018.

(2) The company sold their goods to customers at a lower price in 2019 than in 2018.

(3) The company bought the goods for resale from their suppliers at a higher price in 2019 than in 2018.

(4) The company bought the goods for resale from their suppliers at a lower price in 2019 than in 2018.

(1) and (2)

(2) and (4)

(2) and (3)

(1) and (4)