By Catherine Morrison -CP-Prime Minister Mark Carney is hosting Canada’s premiers in Ottawa Friday as the provinces grapple with the effects of Chinese and U.S. tariffs. The meeting at the Canadian War Museum is taking place just days before Carney is expected to launch a federal election campaign that would send Canadians to the polls as soon as April 28. Audrey Champoux, a spokesperson for Carney, said earlier this week the session offers a chance to discuss ways to create a single Canadian economy, instead of 13 separate ones. Saskatchewan Premier Scott Moe said Thursday his priority for the meeting with Carney is to discuss China’s tariffs on Canadian canola oil and meal. Beijing imposed the tariffs in response to Canada’s levies on Chinese-made electric vehicles, steel and aluminum. “(This…