Math Spies in London Question 1

In an undisclosed location near Seattle, Washington, Math Spies has a secret training ground.  The director wants you to call her at 4:15 P. M. BST.  What time do you need to call her PDT?

A. 8:15 A. M. PDT

B. 8:15 P. M. PDT

C. 4:15 A. M. PDT