The correct answer is (c). The inside pressure of a soap bubble is less than the atmospheric pressure. This is because the soap film has surface tension, which pulls the film together. The surface tension of the soap film creates an inward force that pushes on the air inside the bubble. This inward force is greater than the outward force of the air pressure, so the pressure inside the bubble is less than the pressure outside the bubble.
Option (a) is incorrect because the inside pressure of a soap bubble is not equal to the atmospheric pressure. Option (b) is incorrect because the inside pressure of a soap bubble is less than the atmospheric pressure. Option (d) is incorrect because the inside pressure of a soap bubble is not none of the above.