Answer: First option is correct.
Step-by-step explanation:
Using the inscribed angle theorem, which states that the angle inscribed at the center is half of the sum of measure of its intercepted arcs.
So, m∠BFG is the inscribed angle.
And its intercepted arcs are BG and CD.
So, According to theorem,
![m\angle BFG=\frac{GB+CD}{2}](https://tex.z-dn.net/?f=m%5Cangle%20BFG%3D%5Cfrac%7BGB%2BCD%7D%7B2%7D)
Hence, First option is correct.