It's D because a checklist is to help you organize a list of things like groceries, homework etc. It can sperate indormation..for example, homework need to be separated so we won't messed up on which is which. It can also portray information clearly because you're making a check list.
Yes, if you download an app such as gmail or yahoo mail. hope this answered your question.
Giga usually means 10^9
We're trying to work giba, which is 2^30 into the vocabulary to differentiate them because of the confusion and difference that they create.
