Final answer:
The output of the code will be undefined.
Step-by-step explanation:
The code will output undefined.
When the code is executed, the variable b is initialized with the value 1. Inside the function outer(), a new variable b is declared and assigned the value 2. Then, inside the function inner(), a new variable b is declared and assigned the value 3. However, before this assignment, the line b++; is executed. Since b has not been assigned a value yet, it is undefined at this point. Therefore, the output of this code is undefined.