I always try to be happy but i can't..
which sentence is this​

Can you me find area of the shaded region?

Two technicians are discussing how to test a car's exhaust by holding a small piece of paper within an inch of the tailpipe mouth. technician a says that if the paper is vibrating due to a "puffing" output from the tailpipe, this signals a smoothly running engine. technician b says that if the paper is being drawn toward the tailpipe, this could indicate burned exhaust valves. who is correct? a. technician b b. both technicians a and b c. technician a d. neither technicians a or b

When you look at the data about all of the children in your setting, you can learn a. about child development. b. how well each individual child is performing. c. what outside factors you need to change. d. how effective your instruction and environment are.