Consider the following relations from A to B where
A={u, v, w, x, y, z} and B={p, q, r, s}.
1. {(u,p),(v,p),(w,p),(x,q),(y,q),(z,q)}
2. {(u,p),(v,q),(w,r),(z,s)}
3. {(u,s),(v,r),(w,q),(u,p),(v,p),(z,q)}
4. {(u,q),(v,p),(w,s),(x,r),(y,q),(z,s)}
Which of the above relations are not functions ?

Options

A. 1 and 2
B. 1 and 4
C. 2 and 3
D. 3 and 4

Answer

C

Explanation

Given that, A={u, v, x, y, z}, B={p, q, r, s}
As we know, a mapping `f : x rarr y` is said to be a function, if each element in the set x has its image in set y. It is also possible that these are few elements in set y which are not the image of any element in set x. Every element in set x should have one and only one image.

(ii) and (iii) are not function.