Answer:
Increase in demand, then increase in prices
Step-by-step explanation:
Note that the law of demand and supply also applies to the housing market.
Thus when developers notice increase in the demand for houses; leading to an increase in prices for houses, this necessitates the increase in developer construction so as to make more profit.
Remember, this developers likely had undeveloped land they bought for some time, and so its an opportunity to reap more investments.