What? How? You choose the specific product you want from a specific seller or reseller on Amazon.
To give customers the best possible shopping experience, Sellers must meet performance-based requirements to be eligible to compete for Buy Box placement.
All Buy Box eligible offers are then further evaluated to determine the Buy Box winning offer. One "New" and one "Used" condition offer, as applicable, will receive Buy Box placement.
https://www.amazon.com/gp/help/customer/display.html/ref=hp_...
--- No reason to think Alexa will work differently