The answer is C. 1.5dm
Step-by-step explanation:
Use the "King Henry Died Monday Drinking Chocolate Milk" to remember the scale which is "Kilo, Hecto, Deca, Meters, Deci, Centi, Milli"
This goes from the largest--kilo--to the smallest--milli.
We have 150 millimeters, so you start at "milli" to get to decimeters, you jump 2 spaces up the scale, so you take the decimal point and move it two spaces up the number and get 1.50 decimeters