A risky portfolio is made up of Stock A and Stock B. The optimal weights of Stock A and Stock B are 30% and 70%, respectively. Stock A has an expected rate of return of 12%, and Stock B has an expected rate of return of 9%. Treasury bills pay 4.20%. What proportion (weight) should be invested in the Treasury Bill to form a complete portfolio with an expected rate of return of 9.25%?

a. 19%

b. 11%

c. 10%

d. 8%

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