An investor invests 70% of her wealth in a risky asset with an expected rate of return of 15% and a variance of 5%, and she puts 30% in a Treasury bill that pays 5%. Her portfolio's expected rate of return and standard deviation are _________ and _________ respectively. a. 10%; 6.7%b. 12%; 22.4%c. 12%; 15.7%d. 10%; 35%