It appears that the Q1(b) does not, in fact, include labels on its data flows.
It is probably not how I would have done it but here is the rationale as I would see it:
Flows to and from well-named data stores could be regarded as implicit (the flow from a "flight details" can only be flight details). Similarly the author seems to have assumed that it is obvious what data the customer is providing though this is arguably a dangerous assumption! They may have decided that labelling made the diagram less readable.
Obviously you won't lose marks for a diagram that is consistent with the one provided though clearly the flows must be clear - a store labelled "Database" with an anonymous flow for example would be marked down both on poor naming of stores and lack of detail on the flow.
Apologies for the confusion.