If the put options on a stock with strike prices $18 and $20 cost $2 and $3.50, respectively. The two options can be used to create a bull spread if an investor buys the __(a)__ ($18 put or $20 put) and sell the __(b)__ ($18 put or $20 put). This strategy gives rise to an initial cash _____(c)_____ (inflow or outflow) of $___(d)___.

Stock Price	Payoff	Profit
ST 20	(e)	(h)
18 ST 20	(f)	(i)
ST 18	(g)	(j)

Provide the information that is missing in the question in order.

(10 marks)