Left Riemann Sum Expression

Question

Using the graph of $$f(x)=2*x+1$$ shown above, which of the following expressions correctly represents the left Riemann sum approximation with 5 equal subintervals over the interval [0,5]?

Accepted Answer

$$[f(0)+f(1)+f(2)+f(3)+f(4)]*\Delta x = (1+3+5+7+9)*1=25$$

Answer

$$[f(1)+f(2)+f(3)+f(4)+f(5)]*\Delta x = (3+5+7+9+11)*1=35$$

Answer

$$[f(0)+f(1)+f(2)+f(3)]*\Delta x=(1+3+5+7)*1=16$$

Answer

$$\frac{f(0)+f(5)}{2}*5=(1+11)/2*5=30$$