Best #'s 1 and 2. Two needs to be cropped on the right side, enough to remove the silhouetted bush in upper right corner. That would strengthen the diagonal of the cactus. #1 could stand a top trimming there is a bit to much sky and the top 1/3 of third of that 'framing tree adds nothing to the photo. #3 & 4 have no interest or focus points 3 might work as a BW and some work on the dynamic range...or merely a lot of work on structure and trim. Top trim on it would be in order as well imo