The total number of muffins baked by Mary is 34 muffins.
If she gives her neighbor 17, let us assume that the amount left is x muffins.
The sum of 17 and x will give us the total number of muffins, which is 34. Therefore, we have the equation representing this situation to be:
![x+17=34](https://img.qammunity.org/2023/formulas/mathematics/college/sz0v20s8j67oelcz0y8io32h8j9uu7m6dq.png)
We can solve for x by subtracting 17 from both sides of the equation:
![\begin{gathered} x+17-17=34-17 \\ x=17 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/scfw81d8hcok6excwlo024jmqtzn27glhq.png)
Therefore, the correct option is the THIRD OPTION.