There are lots of cues to suggest the winning idea here. One prominent pattern is the presence of three Black pieces lined up on the c-file. This should cause you to think about tactics that take advantage of enemy pieces on a line: pins and skewers. And if you size up the protection each Black piece enjoys, you see that the bishop on c7 is protected only by the queen in front of it—another tip-off. The natural thought would be to put a rook on the file, as with Ra-c1. The rook has the protection it needs to attack Black’s queen, and the queen has nowhere to go that still protects the c7 bishop. White plays RxB next move.