For the Data $(0,10),(1,20),(2,30),(3,40),(4,60),(5,80)$ , Where the First Number in Parenthesis Is

Multiple Choice

For the data $(0,10) ,(1,20) ,(2,30) ,(3,40) ,(4,60) ,(5,80)$ , where the first number in parenthesis is $t$ and the second number is the actual demand, if we fit a trend line of the form $y t=a+b t$ , the value of $b$ obtained using the appropriate formulae is

A) 5.0
B) 10.0
C) 13.71
D) 5.71
E) 0