Answer:
C). Onetime.
Step-by-step explanation:
According to the entry of AP Stylebook, the correct word to be employed as per the given context would be 'onetime' that implies the meaning 'former' to the sentence. Thus, the sentence would imply that 'the 'former'(onetime) luxury vessel is larger than the Titanic and still capable to hold the record of fastest trans-Atlantic passenger ship crossing.' The other two options(one-time implies 'once' and one time is written incorrectly) propose either an out of the context meaning that fails to deliver the intended essence of the statement or offer an incorrect formation. Therefore, option C is the correct answer.