First let's turn that model into an equation
3x + 4 = 2x + 6
The first step would most likely be to subtract 4 from both sides.
When dealing with an equality, you have to the same operation to both sides.
Subtracting 4 from both sides would be the same as adding 4 negative tiles to both sides.
The first choice is your answer.
Have an awesome day! :)