"Adobe Acrobat DC" is the new marketing buzz for the Acrobat & Adobe Reader products.
It makes things rather confusing.
There is Reader (formally known as Adobe Reader) that is now Adobe Acrobat Reader DC.
There is Acrobat Standard (Adobe Acrobat Standard DC).
There is Acrobat Pro (Adobe Acrobat Pro DC).
Sooo -- Reader is a PDF viewer. Reader DC provides the same Comment/Drawing Markup tools that are available with Acrobat Standard DC and Acrobat Pro DC.
BUT, unlike Acrobat Standard or Pro "Reader" cannot:
--| create PDF
--| modify PDF page content
--| export PDF page content
As well, Reader DC Does Not have the tools / features available in Acrobat Standard or Pro
Reader is free. Acrobat Standard / Acrobat Pro are not free -- you must purchase the license then you can obtain and use the desktop application.
Reader provides no PDF Optimizer, no Preflights, no OCR, etc.
Be well...