Starting the clock

[JugglingReferee]

Originally Posted by cowboys

I'm a bit confused on this rule.

On 2nd and 10 A runs the ball for five yards. The clock is obviously running. On the next play, A throws an incomplete pass, there is a holding penalty called on A. B accepts the penalty.

Does the clock start on the snap because the play in which there was a penalty stopped the clock, or does it start on the ready for play because the clock was running before the play that included the penalty?

CANADIAN RULING:

Before the 3-minute warning: on the RFP.
After the 3-minute warning: on the snap.