Answer:
Option B
Step-by-step explanation:
For answering this question we must understand what is a function.
A function is different from mapping.
Mapping is just a subset of AxB where A and B are two sets.
But function is constrained to the point that elements of I set will have unique image in second set.
We find From the options
But in option B,, we find that 1 has two images 3.3 and 4.5. i.e. 1 does not have unique image. Hence not a function.
All other options the first element in ordered pair have a unique image.
Hence all other options are functions.
Only option B is not a function.