[Oquilla's Flower] Enormous Crocodiles quest line

How to trigger this quests line from black spirit?
https://bdocodex.com/us/quest/3719/1/

 

This is a Special Quest, in order to get it you have to do Special Barter.
You can obtain a Quest Voucher to use and receive one of the following quests.
(Each quest rewards Oquilla’s Flower x100 and can be repeated.)

• [Oquilla’s Flower] Enormous Crocodiles – kill Saltwater Crocodiles x5
• [Oquilla’s Flower] Hungry Sea Creatures – Complete 20 barters
• [Oquilla’s Flower] Iridescent Coral – Kill Hungry Hekaru x15 and Hungry Oceanstalker x15
• [Oquilla’s Flower] Supplying Food – Catch and hand in Tuna x1 and Red Tilefish x1
• [Oquilla’s Flower] Talented Barterer – Hand over Iridescent Coral x5

https://www.blackdesertfoundry.com/ebenruths-nol-guide/