The expression 'at a pinch' as used in option (2) is correct and is used to mean if completely necessary. In option (3), the most common usage of word pinch has been given which refers to a squeeze made by fingers and thumb on a surface. In option (4), pinch refers to the experience or effects of poverty. In option (1), neither the sentence make any sense nor the correct form of word pinch has been used which instead should have been 'pinched'. Therefore, option with incorrect usage of given word is option (1).