Final answer:
A 'write off' refers to a tax deduction for business-related purchases. Without context, it's unclear what David bought, but it would be something that serves to reduce his taxable income through the allowed deductions.
Step-by-step explanation:
The question seems to be referring to a purchasing decision made by a person named David, who bought something specifically to take advantage of a tax deduction or a 'write off'. In a business context, a write off is a deduction that businesses or individuals can take to reduce their taxable income by deducting the cost of eligible expenses or purchases. Without additional context, it's challenging to specify what David bought as there are many possibilities. Common write off expenses could include business supplies, a vehicle for business use, or equipment relevant to a person's profession. The nature of the purchase often depends on David's line of work or the specific regulations that govern tax deductions in his jurisdiction.