Filter scanning technique calls for placing probe at distance X from the downstream face of filter and traversing in overlapping strokes at rate that does not exceed Y. a. X = 1 centimeter, Y = 1 centimeter per second b. X = 1 inch, Y = 2 inches per minute c. X = 1 inch, Y = 1 inch per second d. X = 1 inch, Y = 2 inches per second. e. X = 1 centimeter, Y = 2 centimeters per second