zoom lens upgrade,maybe?

[Mad Aussie]

Without testing them it's hard to say exactly but I'd vote on the 70-200 L being the sharpest thought out due to the focal length not being as long in range as the other two. The more a lens has to zoom, the less likely it can retain the same sharpness along the full range of zoom it has.

Having said that, I'd get the 18-200 and learn to sharpen your photos well in post.