Answer:
d) 
because that would be the same as 
Do you need the area of the floor plan? If so here you go:
6*4 = 24, so 24 cm.
Ok if the number behind the decimal is 4-0... round down, But if the number is 5-9 round up.
Example:65.85
The number behind the decimal is a 8.. So round this number up to the next availible whole number, which is 66.
