Hmm: Which one of these 501c(3) organizations is not like the other?

Heartland Institute faces fresh scrutiny over tax status | Environment | guardian.co.uk

John Mashey, a retired computer scientist and Silicon Valley executive, said he filed a complaint to the IRS this week that said Heartland's public relations and lobbying efforts violated its non-profit status.
Mashey said he sent off his audit, the product of three months' research, just a few hours before the unauthorised release of the Heartland documents.
..."I believe there was a massive abuse of 501c(3)," Mashey said. "My extensive study of these think anks showed numerous specific actions that violated the rules – such as that their work is supposed to be factually based. Such as there was a whole lot of behaviour that sure looked like lobbying and sending money to foreign organisations that are not charities."

The Climate Project - Info | Facebook

The Climate Project is Al Gore's climate change leadership program and is a part of the Alliance for Climate Protection, a 501(c)(3) non-profit organization.

About Greenpeace Fund | Greenpeace

Greenpeace Fund, Inc. is registered with the Internal Revenue Service as a 501(c)(3) charitable entity

Make a Monthly Donation | World Wildlife Fund

World Wildlife Fund is a 501(c)(3) charitable organization.

NRDC: NRDC Action Fund

NRDC operates under section 501(c)(3) of the tax code

Contact Us - Gift Planning - Sierra Club

The Sierra Club Foundation (currently located at 85 Second Street, Suite 750, San Francisco, California, 94105) is a "public foundation," incorporated in the State of California and classified as tax-exempt under Internal Revenue Code 501(c)(3).

Charity Disclosure

The Pew Charitable Trusts is a non-profit, 501(c)(3) tax-exempt organization