A table that represents a proportional relationship will be the one in which every element in y is a constant multiple of the corresponding element in x.
In other words, the points of the table must lie on a line that must pass through the origin.
Let us check each of the tables one by one.
Table 1.
and
The difference between the two points is the same BUT every element in y is not a constant multiple of x; therefore, this choice is not correct.
But just to make sure, let us go through other remaining two tables.
and
these two slope are not the same; therefore, this is not the right table.
Now for the third table.
and
This table is the correct answer!
Let us now do table 4
and
the two slopes are not equal; therefore, this table does not represent a proportional relationship.
Hence, the third table is the correct one.