Answer:
A, C and D
Explanation:
A: y = 7 is a straight, horizontal line
B: is a parabola. Discard
C: (cannot read denominator) This is a straight line thru the origin.
D: This is a straight line.
E: This is a parabola, due to to the x^2 term. Discard
F: This is a circle. Discard
Straight lines here are A, C and D