3. A
The relation between V and I at constant R is;
V=IR, so it is a direct linear relation.
4. A
This is another direct linear relation as P=IV
5. D
The relation between P, R, and V is P=[tex] \frac{V^2}{R} [/tex], so P is inversely proportional to R.
6.B
The relation between P,I, and R is [tex]P=I^2R[/tex], so P is directly proportional to the square of I.
Please note that y:x relations are always straight lines while [tex]y:x^2[/tex] relations are parabolic lines.
Hope this helps!
