This is irrelevant. The environmentalists don’t imply a switch is only worthwhile if it applies to all vehicles on the road.

This is irrelevant. It doesn’t give any likelihood those efforts will be successful, nor does it say cleaner-burning gasoline would produce more or less benzene.

This fails to distinguish between gasoline and methanol, both of which are discussed as automobile fuel. It doesn’t say a switch from gasoline to methanol would benefit these local economies.

This supports the environmentalists’ proposal. It suggests burning methanol produces a less potent carcinogen than burning gasoline, which implies methanol may be safer than gasoline.

This weakens the environmentalists’ argument. It implies switching to methanol could backfire in the event of a spill, causing more damage to the environment than would gasoline.