Row rank and column rank

In a matrix $\displaystyle A \in \mathbb{C}^{3x7}$, what is the limiting rank? The column rank or the row rank? the maximum rank is 3, but I don't understand if its the row rank or the column rank that's limiting it. I should know this by now.
generally? To find the column rank do you count the number of linearly independent columns and that's the column rank?
and do you do the same for row rank? I mean do you count the number of linearly independent rows and whatever that number is, that's the rank?
If this is the case I would nominate the row rank to be the limiting rank here.

thanks.
david.