Answer: d. gregor was the only working adult and supported the family with his paycheck.
In The Metamorphosis, Gregor is the only provider of his family. With his wages, he supports his aging parents as well as his unmarried sister. This is an accurate depiction of life in Europe at the beginning of the twentieth century. Grete is not supposed to work because she is a woman and is still her family's responsibility, while Gregor's parents rely on his son for support. This situation causes significant mental distress to Gregor.