C.
Assuming things stay the same then the Brewers are really banking on Caleb Durbin and/or Oliver Dunn for that final IF spot.
Outside of that though I don't think the Brewers needed to do much. They have 4 solid Starting pitchers and a slew of young guys who hopefully can step up when injuries occur(plus the Wildcard that is Woodruff)
They return most of what is a very good bullpen from last year
Their OF remains stacked with 2 really good players(Yelich, Chourio), another who has shown real potential(Mitchell), and 2 more who are more than capable of playing in the bigs(Frelick, Perkins)
And lastly in the IF Ortiz & Turang return, both of whom are young and had solid years last year. Hoskins returns who wasn't great last year but provides much needed power at least. We'll see if we get anything from Black.
Long story short, the Brewers didn't do much, but also the only spot I question heading into Spring Training is that final IF spot