Final answer:
When a purchaser pays money to a builder, it is considered to be a trust fund.
Step-by-step explanation:
The correct answer is B) a trust fund.
When a purchaser pays money to a builder, it is often held in a trust fund. This means that the builder does not have immediate access to the funds and they are set aside and held in trust until certain conditions are met or the work is completed to the satisfaction of the purchaser. This helps protect the purchaser's investment and ensures that the builder cannot misuse the funds.