Your first problem is figuring out how to remove some of the 3 hit blocks to have some room to work to the middle and take care of the bomb. Only 15 moves, it takes some work. Try to match the candies in middle portion to hit 2 blocks at a time with a piece to make it easier on you. All the 3 hit blocks are Jelly spaces as well, so you are going to end up doing it 4 times per spot. If you can zip a horizontal or vertical striped candy through the middle to kill the bomb that would be ideal, but far from frequent on occurrences.
Thanks to Matthew Dean
Patricia Frederick’s Tips for Candy Crush Level 143
The most difficult part of this level is getting to the bomb. Once it’s removed, keep hitting the blocks to get to the jellies underneath. A color bomb/striped candy combo is good here as well as a striped/wrapped combo.