The correct options are
B Oxidising power of F2 is maximum
D Oxidising power is in order F2>Cl2>Br2>I2
A. The standard reduction potential of fluorine is most negative. Hence, the oxidizing power of fluorine is maximum. Thus, the option A is correct.
B. The standard reduction potential of iodine is least negative. Hence, the oxidizing power of iodine is minimum. Thus, the option B is incorrect.
C. and D. On moving down the group, the oxidizing power of halogens increases in the order F2>Cl2>Br2>I2. Thus, option C is correct and the option D is incorrect.