Which of the following statements is correct regarding order of reaction

1) Molecularity of first order reaction can be one, two (or) threeEx: Let us consider certain first order reactions. Elementary reactions are given asA → Products - I2A → Products - IIMolecularity in I is 'I' and II is '2'(2) order can be negative alsoEx: Conc. for a reactant increased by 2 times where rate becomes half  2x =2-1  (3) order is not the sum the coefficients of a stoichiometric equation.(4) It must be experimentally determined.