#### Answer

The best estimate is b. $2050~cm^2$

#### Work Step by Step

If the television screen had a width of 50 mm and height of 40 mm, the area would be $2000~mm^2$. Since this screen would be too small, answer a. $2050~mm^2$ seems unreasonably small.
If the television screen had a width of 50 cm and height of 40 cm, the area would be $2000~cm^2$. Since the height and width of this screen seem reasonable, answer b. $2050~cm^2$ seems like a good estimate.
If the television screen had a width of 50 dm and height of 40 dm, the area would be $2000~dm^2$. Since the height and width of this screen would be several meters, this screen seems too large. Therefore, answer c. $2050~dm^2$ seems unreasonably large.
The best estimate is b. $2050~cm^2$