Which First

 is the thirty-eighth level of Bloons Junior.

Completion
To complete this level, note that the following order is Tack Bloon, Lightsaber Bloon, Spiky Bloon, meaning that you have to pop the Tack Bloon on the bottom left, then pop the Lightsaber bloon on the bottom left, then pop the Spiky Bloon on the top.

Trivia

 * Referring to the level name, the Tack Bloon on the bottom left should be popped first.