What is the size of the expanded background image required for expandable click-to-play YouTube Video Ad?
A. 300×35
B. 50×50
C. 950×500
D. 300×225
What is the size of the expanded background image required for expandable click-to-play YouTube Video Ad?
A. 300×35
B. 50×50
C. 950×500
D. 300×225