Bin are a user-defined grouping of numerical data in the data source.
According to the official Tableau documentation: It's sometimes useful to convert a continuous measure (or a numeric dimension) into bins.
Have a look at the following image. When we right click a measure, we get the following options:

However, for a dimension (this is because the DATA TYPE of this dimension is a string:

But what if we have a dimension of type NUMBER (NUMERIC DIMENSION)? See below:

We can clearly create bins from dimensions too - they just have to be numeric :) For more information, please refer to : https://help.tableau.com/current/pro/desktop/en-us/calculations_bins.htm

Explanation
From the official documentation, the following are the major advantages of using Tableau Data Extracts:

From Tableau 2020.2 onwards, .hyper is the recommended way since it is faster than .tde!

Explanation
We can perform filter, URL and highlight actions out of the above given choices on a dashboard. Please refer to the image below:

Explanation
Yes, it is very much possible to use measures in the same view multiple times. For example, refer to the image below:

We are using BOTH the Sum of the revenue and the of the revenue in the same view!

Very important question for the exam and appears quite a lot too.
The correct answer is - By dragging another dimension to Color on the Marks card.

This is what the question says we have already created. Now to convert this into a Stacked bar chart, we will drop another dimension on Color in the Marks card.

The rest won't create stacked bar charts, and hence are incorrect choices. The best way to answer such questions on the real exam is to quickly do what the options say and see if they satisfy the requirements in the question.