<em><u>Question 1:</u></em>
The domain of a function is defined as the input values of the function. Conventionally, they are the values of the x-coordinates of the function.
Therefore, the domain of the given function would be the x-values of the given points.
<u>This means that:</u>
domain is : {0 , 3 , 5 , 8} ................> option B
<em><u>Question 2:</u></em>
For a relation to be a function, each x-value should have one and only one corresponding y-value. Otherwise, it won't be a function.
In the given, we can note that x = 0.3 has two y-values (0.6 and 0.7), <u>therefore</u>, this relation is not a function ...........> option B
Hope this helps :)