Write the next sentence in the following story.

How to improve reaction speed
Test your speed by having a friend drop a card.
Cut a piece of cardstock so that it's about 8 inches (20 cm) long and 2 inches (5.1 cm) wide. Ask a friend to hold it vertically by the top.

Options:
(i) Turn the card so that the curved side is facing up and the stained side is facing down. You can tell that the card contains 100% speed if it has a random number in it.
(ii) At the top, snap one corner open. Make a small hole inside the cardstock so that you can insert the card through, then paint a thin line around that corner.
(iii) See if they're able to add weight with their fingers. If they can't, let them sit on the floor.
(iv) Line up your fingers with the bottom edge of the card and ask your friend to drop the card without warning. When the card is dropped, grab the card with your fingers as quickly as you can.. The answer should be
(iv)