Question 1:
For this case we have that by definition, the slope of a line is given by:

Where:
are two points through which the line passes.

Substituting in the equation:

ANswer:
Option C
Question 2:
For this case we have that by definition, the slope of a line is given by:

Where:
are two points through which the line passes.

Substituting in the equation:

ANswer:
Option A
Question 3:
For this case we have that by definition, the slope of a line is given by the following formula:

Where:
are two points through which the line passes.
We have as data:

Substituting in the formula:

We substitute each of the points and see if the equality is met:
Point A: (6,8)

Equality is met.
Answer:
Option A
Question 4:
For this case we have that by definition, the slope of a line is given by the following formula:

Where:
are two points through which the line passes.
We have as data:

Substituting in the formula:

We substitute each of the points and see if the equality is met:
Point A: (-3,0)

It is not fulfilled!
Point B: (6, -2)

Equality is met!
ANswer:
Option B