Algorithms | Analysis of Algorithms | Question 9

In a competition, four different functions are observed. All the functions use a single for loop and within the for loop, same set of statements are executed. Consider the following for loops: 

A) for(i = 0; i < n; i++)

B) for(i = 0; i < n; i += 2)

C) for(i = 1; i < n; i *= 2)

D) for(i = n; i <= n; i /= 2)

If n is the size of input(positive), which function is most efficient(if the task to be performed is not an issue)?