Correct option is C
Assertion is correct as Lien is the right to retain possession of goods of another person till a certain claim upon that person is not satisfied.
Unpaid seller is granted a lien over the goods of the buyer until the price is not paid by the buyers.
Reason is not correct as an unpaid seller in possession of goods sold is not entitled to exercise his lien on the goods where the goods have been sold without any stipulation as to credit.
Lien is available only if the following requirements are fulfilled.
Buyer has not paid or offered to pay the whole price to the seller
No credit is given to the buyer if given credit period has expired.
Negotiable instrument which was conditional payment to the seller has become insolvent
Buyer has become insolvent.