Paved for 5 years with gate opening onto Property A? That looks like “continuous open and notorious”
https://schorr-law.com/prescriptive-easement-transfer-with-the-sale-of-the-property/
When a Prescriptive Easement Has Ripened
In the event a prescriptive easement has ripened,
it generally transfers with the sale of the property, even though
it will not appear on title. First, the transfer of propertyusually includes all of the rights, privileges, powers and immunities incident to the ownership of the property. In addition, once a prescriptive easement ripens,
it will continue in perpetuity, unless it is otherwise terminated.