ACI Dealing Certificate (#308)

What is the meaning of “under reference” in the terminology of trading?

a term the quoting dealer uses to caution the receiver of the quote that the price may have to be re-quoted at the receiver’s risk
the qualification that the rate quoted in the market may no longer be valid and requires confirmation before any trades can be agreed upon
the statement that the rates quoted by the broker are for indication only
an acknowledgement by the dealer receiving the quote that the rate may have to be re-quoted at the receiver’s risk