World 3-B (New Super Mario Bros. 2)
From the Super Mario Wiki
Completing this level will unlock World 3- skipping World 3-Ghost House and World 3-5.
Mario begins in front of two ? Blocks in a forest, one of them containing a Mini Mushroom. Then, Mario has to swim past the wall through a small pool of water. There will then be a fork in the path. The player can choose to take either the yellow pipe or red pipe. Either way, warping through any will take Mario to an autoscrolling beach area.
Both pipes lead to the same area, a jungle area with a small pool of water and the flagpole. If Mario took the red pipe earlier, he will come out from the pipe on an elevated orange platform, allowing Mario to easily touch the top of the flagpole.
To find Star Coins in this level, Mario must take the red pipe path.