We experience fictitious forces due to: a. Rotation of a reference frame b. Inertial reference frames c. Translational motion d. Universal gravitation.

A fictional force (also called force of inertia, pseudo-force, or force of d'Alembert, 5), is a force that appears when describing a movement with respect to a non-inertial reference system, and that therefore it does not correspond to a genuine force in the context of the description of the movement that Newton's laws are enunciated for inertial reference systems.

The forces of inertia are, therefore, corrective terms to the real forces, which ensure that the formalism of Newton's laws can be applied unchanged to phenomena described with respect to a non-inertial reference system. The correct answer is A.