Adult Clover (7-B to High 7-A) is more threatening. 7-B version might take one good nuke, but High 7-A would require tremendous amount of hits to take down. All nukes combined are 6-C, so overall humans would have enough nukes to defeat Adult Clover and still have some left up. Plus, Clovers are not resistant to radiation, so they might end up dying of cancer long before they manage to kill every human.
Now then: which one of the two should i use? Or how many Adult Clovers i should use?
If we want a fair match, I'd say that the High 7-A Clover would be best. Since it's just one monster, all of humanity's forces would likely focus on it, which would likely harm it. Even if it wouldn't kill it, it would still slow it down and cause other harms.
If pelting Clover with many nukes, one after another, there would likely be enough damage to take him down. Since he's in the middle of Atlantic Ocean, there's not many people around, so using nukes is acceptable. Since there's 1 month of preparation time, there is more than enough time to set up nuclear weapons in that area.
Clover is resistant to Poison, but Radiation is another thing entirely; Clover can end up dying due to radiation sickness from direct impacts of thousands of nukes.
Clover is at least Subsonic (tier-wise, about as fast as Po-2), but possibly moves at Supersonic+ to Hypersonic speed (about as fast as certain Cruise Missiles). Clover doesn't have Range great enough to shoot down airplanes or missile, as many airplanes fly at higher altitudes than Clover can reach (higher than clouds). As such, all aircraft used to drop nukes on Clover would safely return - and it's not likely that Clover could destroy them at airport, since said aircraft could re-locate onto another airport before Clover shows up.
Clover may try to dodge nukes - but it may not work, since Clover is a very big target. Plus aircraft/missiles are homing (correct trajectory mid-flight), and may be faster than Clover (depending on how you interpret him).
If Clover is somehow still alive after all nukes are dropped on him (very unlikely turn of events), high-tier conventional weapons (e.g. cruise missiles) can be used. Since Clover can't shoot down aircraft, they would just keep whittling him down, like mosquitoes around the cow. Since Clover would be either dead or extremely heavily damaged after being hit with all nukes, he would be sick enough to get finished off by conventional weapons.
Humans may also use chemical or biological weapons on Clover. It's weaker than nukes, but it can also cause noticeable damage, especially if Clover is already weakened - due to pathogens multiplying and chemical weapons having very small lethal dose - so that there may be enough substance to damage him in massed use.
Humans always see Clover from space by satellites - while Clover's field of view is limited by his eyesight and height.
Humans may survive after using all nuclear weapons (at least, enough to claim victory); some would survive in bunkers or fallout shelters.
I vote Human Race.
