Is it illegal to have no banister on a public staircase?

Yes in the UK. In the United Kingdom, there are regulations which involve the usage of bannister in public staircase such as those found in malls and on the subways. They even require public staircases to have a width of 1800mm at max only. If it’s more than the mentioned measurement, flights should be divided.

answer is b shrapnel injuries

the density would be a smaller number.