Universal Container’s Salesforce admin wanted to convert long text area field to a formula field. What will happen to the images of the field due to this conversion?

Answer options:

A.Any images will be deleted once the conversion happens
B.The data in the records will be truncated to the first 255 characters of the field
C.You cannot convert long text fields to formula fields
D.Data loss will happen upon the conversion

Correct Answer: C 
You can’t convert long text area fields to a formula field and you can’t convert a formula field to the long text area fields since formula fields are read-only fields. 
Option A is incorrect because you can’t convert a long text area field to formula field. Images will be deleted upon saving (This will happen the second time you save the record) when you convert rich text area fields to long text area fields. 
Option B is incorrect because data in the records will be truncated to the first 255 characters only when you convert long text area fields to either email or phone or text or text area or URL field 
Option D is incorrect. Data loss will not happen since the conversion will not work. 
Reference: 

https://help.salesforce.com/articleView?id=notes_on_changing_custom_field_types.htm&type=5