Select the most appropriate option to substitute the underlined segment in the given sentence. If no substitution is required, select No improvement. Though many European traders visit Puducherry in the sixteenth century onwards, what remains today is a relic of its French past.

• A. trader visit Puducherry from the sixteenth century onwards
• B. No improvement
• C. traders visited Puducherry in a sixteenth century onward
• D. traders visited Puducherry from the sixteenth century onwards