According to the IRS, it is 501(c)(3)

People.

Yes, it qualifies as a tax exempt 501 C3 entity

Associations usually are 501 (c) 4s and charities are 501 (c) 3s. The difference is that 4's cannot accept charitable donations and 3s can.

This would be spelled 501(c)(3) and stated as "five-oh-one C-three".

It refers to a section of the US Internal Revenue tax code 501(c)(3) which designates a tax-exempt non-profit organization of a religious, charitable, scientific, or similar function. These are normally precluded from political contributions and their lobbying activities are restricted.

The text is labeled "Section 501, subsection C, paragraph 3".