Which of the following is a tool used for creating and sharing online learning games?

The correct option is Kahoot.

To understand why this is the correct answer, let's look at the primary function of each of the tools listed in the options:

1. Kahoot: This is a widely used game-based learning platform. It allows educators and users to create, share, and play interactive multiple-choice learning games (often called "kahoots"). These games can be played in real-time by groups of students or self-paced for review, making it a dedicated tool for online learning games.

2. Mentimeter: While it is an interactive presentation tool used to engage audiences through quizzes, polls, and word clouds, its primary focus is on interactive presentations and gathering real-time feedback rather than being a dedicated game-creation platform.

3. Padlet: This is a digital canvas or bulletin board where users can post notes, links, images, and documents to collaborate. It is used for organization and collaborative sharing, not for creating learning games.

4. Zoom: This is a video conferencing and online meeting platform. While it enables remote learning and communication, it is not a tool designed to build or host learning games directly.

Therefore, Kahoot is the specific tool designed for creating and sharing online learning games.