I am getting ABD but the ans is BC. please verify
Notice step 1in my image Br attacks on the carbon it attacks to generate a more stable intermediate not because it is less hindered.
Option A- Bromine attack first carbon of propene because of the formation of 2 degree free radical not because of less hindrance.
Option B-instead of HBr if we used HF the the bond energy is more than Hbr so it requires energy that why it’s endothermic and in case of HI the bond energy is less than Hbr of it releases energy that why it’s exothermic.
Option C-in Ccl3br the radical will •Ccl3 and rest step as same as Hbr reaction
OptionD- Rate determining step is not the first step .
It is the stability of free radical .