Ringo currently invests all of his funds into Dabber Inc which has a standard deviation of 20%. Assuming he moves 40% of his funds into Hertz Inc, which has a standard deviation of 5% and -0.4 correlation with Dabber Inc. Which of the following would describe the change in the risk (standard deviation) of Ringos' portfolio?

a) Decrease by 8.65%

b) Increase by 8.65%

c) Decrease by 4.88%

d) Increase by 4.88%

e) Decrease by 5.88%