Identify the sentence structure problem in each of the following: sentence fragment, comma splice, misplaced modifier, fused sentence, lack of parallelism, or unclear antecedent.

$16.$ The number of employees who took the buyout offer was much higher than expected, now the entire company is understaffed.

$17.$ The leader in Internet$-$only banking.

$18.$ Diamond doesn$$t actually sell financial products rather it acts as an intermediary.

$19.$ Helen$$s proposal is for not only the present but also for the future. $-$unclear

$20.$ When purchasing luxury products, quality is more important than price for consumers.