You are managing a portfolio of 10 stocks which are held in equal dollar amounts. The current beta of the portfolio is 1.55, and the beta of stock a is 2.0. If stock A is sold and the proceeds are used to purchase a replacement stock, what does the beta of the replacement stick have to be to change the portfolio beta to 1.7?

A. 4.4

B. 5.3

C. 3.2

D. 3.5

E. 4.1