Two growing polystyrene radicals, of 400 and 600 monomer units, terminate (ignore initiator fragments). Which outcome is correct?

1. ACombination gives one chain of 1000 units; disproportionation gives two chains of 400 and 600 units, one saturated and one with a terminal double bond
2. BCombination gives two chains of 400 and 600 units; disproportionation gives one chain of 1000 units
3. CCombination gives one chain of 1000 units; disproportionation gives one chain of 500 units twice
4. DBoth modes give one chain of 1000 units, but disproportionation also releases hydrogen gas