What's the best continuation for White?


I like to play Queen Gambit Declined (white) in this variation. 1. What is this variation called? 2. What's the best move for white at this point, and what should be the plan?   


It's very rarely played, Black's usual is 4 ...dxe4.

Most seem to answer 4 ...Bb4 with either 5 cxd5 followed by e5, or with 5 e5 directly, or else 5 Bd2, although GM Jobava played 5 Qb3 last year and won.  All seem playable.