How to continue in this game? I saw the following position and was wondering how white should continue:




Should white exchange bishops?
Should white play a4 to protect the bishop?
Should white play c4 to protect the bishop and undefended pawn on d5?
Should white do something else


Which of the options above, would be the best way to continue and what should be the thought process behind each suggestion.
As white is a pawn down without compensation, piece exchanges should be avoided. White's only practical chance is a king side attack.  Maybe Bc4, with the plan of Bc4-a2, c2-c4, Ba2-b1. Along with Qh5 and/or Qc2 plus g2-g4. Its slow and black can defend, but what else can white try?