The M700 disappeared after 1994 model year until the 1998 CAAD 2's were released. I'm going to assume that it's a '94, which should have come with a Deore LX M560 series from the factory. The clamp diameter is correct at 31.8 mm. You can use at 34.9 clamp one as well, provided it comes with the 31.8 mm shim.
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For informational sake, 7,8, and 9 speed FD are all fundementally the same since the use the same cable pull. Shimano FD's remained pretty much the same until 10 speed and that's when they start to monkey around with them that really complicates things.