Count of the number of options selected in a multi-select drop

So I am having an issue creating a new measure which will count the number of items selected in a multiselect field. so it should return the count of how many options is selected in this field and then I will work on adding formatting later on.

Google Sheets Tutorial – How to Enable Multiple Selection Data Validation Using Apps Script

Google Sheets Tutorial – How to Enable Multiple Selection Data Validation Using Apps Script

Count of Dropdown (multi-select) items in another sheet — Smartsheet Community

Dropdown and multi select - Design Thinking - UX Mastery Community

How to create drop down list in Excel: dynamic, editable, searchable

javascript - Selecting multiple items from dropdown to populate on page - Stack Overflow

Multiple-choice select many

iPhone/iPad: Drop down with size property allows to select multiple options. If shows the count of selected items.

Count of the number of options selected in a multi-select drop down - Questions & Answers - eazyBI Community

Select Multiple Items from a Drop Down List in Excel

Dropdown – Carbon Design System

Google Sheets Tutorial – How to Enable Multiple Selection Data Validation Using Apps Script

Excel Data Validation Tips and Troubleshooting

Have multiple selections in drop down Google Sheets - Web Applications Stack Exchange