Explanation:
An implied warranty is a legal term used to describe the responsibility of a seller to ensure that the goods they sell are fit for their intended purpose and free from defects. There are several types of implied warranties, but one of the options listed in the question is not considered an implied warranty.

Warranty as to undisturbed possession:
This is an implied warranty that guarantees that the buyer will not be disturbed in their possession or use of the goods by any third-party claims. In other words, the seller guarantees that there are no legal claims or encumbrances on the goods that would prevent the buyer from using or possessing them. This warranty ensures that the buyer will have full and uninterrupted use of the goods.

Disclosure of dangerous nature of goods:
This is also an implied warranty, but it is not related to the quality or fitness of the goods. Instead, it focuses on the seller's duty to disclose any dangerous or hazardous nature of the goods to the buyer. This warranty ensures that the buyer is aware of any potential risks associated with using or handling the goods.

Warranty as to quality or fitness by usage of trade:
This is another implied warranty that guarantees that the goods being sold are of a certain quality or fit for their intended purpose. It is based on the common practices or customs of the particular trade or industry. For example, if a buyer purchases a laptop from an electronics store, there is an implied warranty that the laptop will be of a certain quality and suitable for typical laptop usage.

Warranty as to existence of encumbrance:
This option is not an implied warranty. The existence of encumbrance refers to any claims, liens, or other legal restrictions on the goods being sold. While the seller may be required to disclose any encumbrances, it is not considered an implied warranty. The buyer has a separate responsibility to conduct due diligence and investigate any potential encumbrances on the goods before purchasing them.

Conclusion:
In summary, the option that is not an implied warranty is "Warranty as to existence of encumbrance." The other options listed in the question are all examples of implied warranties that protect the buyer's rights and ensure the quality, fitness, and safety of the goods being sold.

Encumbrance means charge. there should be no encumbrance