Alex runs a business that sells the surfboard. He wants to understand their customers' value. After

considering a typical customer's revenue contribution, the cost to serve the customer, the discount rate, and

the customer retention rate, he calculated that the expected value of this customer in period $N$ is $$150.$ He

assumes that this customer makes the same revenue contribution across all periods and that the cost to

serve this customer is the same across all periods. With a discount rate being $5\%$ and a retention rate be $70\%,$

what is the expected value of the customer in period $N+1?$ Choose the closest amount below.

a$.$ $$110$

b$.$ $$100$

c$.$ $$130$

d$.$ $$140$

e$.$ $$120$