Merging Binary Strings

You have two binary strings $A$ and $B$, both of length $N$. You have to merge both the binary strings to form a new binary string $C$ of length $2 \cdot N$. The relative order of characters in the original binary strings $A$ and $B$ should not change in the binary string $C$. For example, if $A = {\color{blue}01011}$ and $B = {\color{red}10100}$, one possible way to merge them to form $C$ is: $C