Multi-choice problem: Continue writing the next sentence in this paragraph:

How to make a walkie talkie
Gather your materials.
For this simple project, you'll need :
Two tin or aluminum cans, or two papers cups five-to-ten meters of string a hammer a nail two tin or aluminum cans will hold up better than plastic ones. The string is less likely to tear through the bottom of a tin or aluminum can.

OPT:
[I] You'll also need a few bobby pins. A wooden dowel or wooden spoon will also work..
[II] If you don't have a tin or aluminum can, you can use metal tongs. See the tips for materials included in this article..
[III] Poke the nail through the bottom of each can/cup. Make the holes in the cans large enough to feed the string through the holes..
[IV] Two pieces of string, or twine, should also work nicely. Another alternative is a bunch of ribbon or long grass..
[III]