When this case isn't too important to "ぐらい, (くらい)", it's used.
Both of "A" and "B" are compared, and when there is no exigency or not important, it's used with "くらい".
In this case , the umbrella is not more important than the bag , so I'm saying "傘ぐらい（傘くらい）".
For example , we assume that I ask a busy person to pass me something .
That person said.
"Please take it yourself about such simple things."
"please do it yourself about such simple things"
This "それぐらい（それくらい）" is also similar meaning and using in that case "傘ぐらい（傘くらい）".