The answer is: b. in a curved path
The Coriolis effect refers to a change in octane currents that influenced by the rotation of the Earth.
In order to prove this, Try to put your finger on top of paper and move that finger on a straight path. After that , rotate the paper with your other hand while still moving the finger on the straight path.
The rotation of the paper would make your finger looked as if its moved in a curved path while it actually still move on a straight path.