A block's plant protection officer urges that the whole of the year's plant protection grant be spent on the leaf-curl fungus, since the number of fields on which the fungus has been found has trebled in a year. Which of the following, if true, most weakens the case for spending the grant in that way?

Trebling describes the shape of a change and says nothing about its size; four fields becoming twelve out of thirty-eight thousand is a trebling of almost nothing. Set against eleven thousand fields under another pest, the fungus cannot be what the whole grant is for. That the fungus is eleven years old in the block tells us it is not new but not that it is small; the number of firms making the chemical bears on supply; and its presence in six villages describes its spread without giving its scale.