Be careful when using the Bulk Update!!
I just added an extra option in a multi pick field, searched and selected 101 candidates that I would like this option to be ticked on the multi-option field and it has erased all the other options that were ticked. This is hours and hours of work that has been erased. I assumed the bulk update would tick the new option with no other impact, not tick the option and delete all ticks in other options.