The number sentence that matches the given word problem is:
A. 7-6 = 1
The word problem asks how much more weight the large crane can lift than the small crane. To find the difference, we subtract the weight capacity of the small crane (6 tons) from the weight capacity of the large crane (7 tons).
Therefore, 7 - 6 = 1, which means the large crane can lift 1 ton more than the small crane.