Bangladesh's match with Afghanistan will be more challenging. Sri Lanka was a weak team against Bangladesh. Meanwhile, Afghanistan is a better team than Sri Lanka, so it will be more difficult for Bangladesh to face Afghanistan.
Both Sri Lanka and Bangladesh are stronger than Afghanistan. The betting odds is slightly in favour of Bangladesh against Afghanistan. But the players of Bangladesh plays with the fear in most of the matches. This is the reason for their defeat in several matches. Anyway, I think Sri Lanka will win against Afghanistan. So, whoever wins between Afghanistan and Bangladesh will qualify for the super four.