We are asked to determine if the given triangles are similar or not.
Let us find the rato of the corresponding sides

So, △GUA and △EFB have two equal sides since the ratio of the two corresponding sides is equal.

Also, notice that the one corresponding angle is equal

Hence, the triangles △GUA and △EFB are similar by SAS theorem since the ratio of two corresponding sides is equal and one included angle is also equal.
Therefore, the last option is the correct answer.