The Smiths ask Jeffrey, who is a qualified builder, to build a house for them on a block of land they have recently purchased. To minimise costs, Jeffery uses defective materials. Three years later, the Smiths sell the house to Jason and Bianca. Jason and Bianca notice that cracks have developed throughout the house and intend to sue Jeffrey under the tort of negligence. Explain whether Jeffrey owes Jason and Bianca a duty of care