Physics of the domino effect

The domino effect is a classic example of a chain reaction: Toppling the first stone in a row of dominoes will bring down the entire row.

At the 2003 edition of the annual Dutch National Science Quiz, the following question was asked:

You topple the first stone of two equally long rows of dominoes. 
In one row, the stones are close together. In the other row, the 
stones are far apart. Which row falls first?

A. The row with the stones far apart.
B. The row with the stones close together. 
C. It makes no difference.

What do you think?

For the Quiz (which is broadcast on national television on Christmas Eve) I was asked to do the experiment and explain the outcome. My explanation was oversimplified, but the best I could do for a TV show. My colleague Hans van Leeuwen provided a much more rigorous analysis. (Here is a more systematic experimental study.)

My clumsy demonstration during the TV show (in Dutch, 6 minutes).