Answer: The second option and the third option are true.
Step-by-step explanation:
The formula of the line in slope-intercept form is:

Where <em>m </em>is the slope and <em>b </em>is the y-intercept.
By definition, the y-intercept in a direct variation is 0.
Therefore, substituting
and
into the equation, you obtain:

Then, the equation is:

As this is a line, it is a linear function.
Therefore, the second option and the third option are true.