Please help me out in optional maths

What are the critical values that correspond to a 95% confidence level and a sample size of 93? a. 65.647, 118.136 b. 59.196, 128.299 c. 57.143, 106.629 d. 69.196, 113.145

The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

The function a represents the cost of manufacturing product a, in hundreds of dollars, and the function b represents the cost of manufacturing product b, in hundreds of dollars. a(t) = 5t + 2 b(t) = 7t - 2t +4 find the expression that describes the total cost of manufacturing both products, a(t) + b(t). a. 7t^2 - 7t + 2 b. 7t^2 + 3 +6 c. 7t^2 + 7t - 6 d. 7t^2 - 3t + 6