Option 1 states that both speed and velocity are vector quantities. This is incorrect because while velocity is a vector quantity, speed is a scalar quantity. A vector quantity has both magnitude and direction, while a scalar quantity only has magnitude.

Option 2 states that both speed and velocity are scalar quantities. This is also incorrect because velocity is a vector quantity. As mentioned before, velocity has both magnitude (speed) and direction.

Option 3 states that speed is a vector quantity and velocity is a scalar quantity. This is incorrect because speed is a scalar quantity. Speed is defined as the magnitude of velocity, which means it does not incorporate direction.

Option 4 states that speed is a scalar quantity and velocity is a vector quantity. This is the correct statement. As mentioned earlier, speed only quantifies the magnitude of an object`s motion, while velocity includes both magnitude and direction. Velocity is represented as a vector with both a numerical value (speed) and a direction.

In conclusion, option 4 is the correct statement, while the other three options provide incorrect explanations.