Consider Example $2$ in Model $1.$ The goal is to prepare an exact replica of the toy rattle shown $($target$)$ using a variety of supplied materials $($starting materials$).$ The amount of supplied materials is more than is needed to prepare the replica of the rattle.

$($a$)$ You shake the rattle and hear that something is inside. How do you know which materials to put inside the checkered tube?

$($b$)$ Look at the egg$-$shaped materials on the ends. Can you determine which eggs to use? Remember this must be an exact replica.

$($c$)$ What is the best way to determine exactly what materials to use to prepare the replica of the rattle?

If you are given a target molecule with no instructions on what starting materials to use and how many steps there are, generate some ideas about how to start $($what reagents and starting materials to use$).$