Please help

12. The researchers decided to drop systolic blood pressure from their model, but add an interaction term between sex and insurance type. The results are as follows: y = 55.5+ -1.3x1 + -6.8x2 + -1.7x3+ 17.7x4 + 2.0x5 where x1 = 1 for female (0 for male); X2=1 for private insurance, 0 for non-private; X3=X1*X2; X4 =1 for black, X5 = 1 for other racial identity. - What is the estimated mean waiting time for males with private insurance who identify as black? a. 63.4 minutes b. 66.4 minutes c. -6.8 minutes d. -8.5 minutes