Mark the correct alternative in the following:

Which of the following are functions?

A function is said to exist when we get a unique value of y for any value of x..If we get 2 values of y for any value of x, then it is not a function..

Therefore, option B is correct .

NOTE: To check if a given curve is a function or not, draw the curve and then draw a line parallel to y-axis..If it intersects the curve at only one point, then it is a function, else not..