9. WBYTW can also deliver internet services at low speed. The low speed is induced by placing a scrambling device for each final user which costs $1 Thus the unit cost of low speed service is $1. The heavy and light users are willing to pay $70 and $5 for the low speed service, respectively. The following table summarizes the information given so far low speed upgrade to high speed # of users Heavy Users $70 $50 50, 000 Light Users $35 $5 130. 000 Marginal Cost $1 -$1 Note: the table represents the marginal values and marginal cost for quality. For example, the Heavy users are willing to pay $70 for the low speed service and $50 for upgrading to the high speed service. Thus they are willing to pay a total of $70 + $50 = $120 for thehigh speed connection. In order to maximize profit, WBYTW should offer: (a) the high speed service at $120 per month and the low speed service at $40 per month (b) only the high speed service at $40 per month (c) only the low speed service at $70 per month (d) the high-speed service at $85 per month and the low speed service at $35 per month