Well, it would depend on what part of my game i am having trouble with at the time. I would focus on a specific area of my game and not just a random club pulled out of the bag.

i tend to pull the 7 out more than anything. however, i do have an old titleist blade 4 iron and sometimes i take it out just to practice hitting center mass. i tell myself if i can hit it then i can hit anything. but yeah man. i hit the 7 for about 20 minutes today.

depends on how I'm putting, wedge unless I'm in need of putting practice.

Putter for sure-

I would roll 5 min of long distance putts to get my speed  right, then I would roll 10 min of 6-10 footers from all around the cup, then I would roll 5 min of 3 footers and in just to get a vision of the ball dropping in the hole

I normally grab my 8 iron or my gap wedge.

Sandwedge !  best way to lower putting numbers is to lower the distance to the pin. Wedge it close and you'll put less.

putter

Putter or wedge.  It's the fastest way to improve your game.  The short game always wins. 

I would practice my putter as it is the club that I use the most during a round.  

I would definitely go with the putter, if you watch the tour, the person that wins every week is the person who is putting the best, and missing the least short putts.

Ben