General Idea:
The measure of one of the central angles of a regular Polygon ([tex] \theta [/tex]) can be used using the below formula:
[tex] \theta= \frac{360^{\circ}}{n} \\\\Where: \\\; n\; is\; number\; of\; sides\; of\; regular\; polygon [/tex]
Applying the concept:
The measure of one of the central angles of a regular octagon.
The octagon have 8 sides, using the above formula we get...
[tex] \theta= \frac{360}{n} \\\\\theta = \frac{360}{8} = 45^{\circ} [/tex]
Conclusion:
The correct option is A) 45 degrees
