Malden Mayor Gary Christenson is seriously considering moving Malden’s City Hall to the second floor of an office building on Exchange Street, he said last week. The city put out a request for relocation proposals in November and received three from Malden landowners, including one in which the city would lease approximately 30,000 square feet of office space on the second floor of 200 Exchange St., property owned by KBS Realty Advisors. Christenson said the he wants to move out of the current City Hall at 200 Pleasant St. and have it demolished as quickly as possible. Moving into rented space would allow that to happen by the spring. “We’re trying to be creative and fiscally prudent,” he said. The city is also considering another proposal that calls for a new City Hall to be built at corner of Ferry and Centre streets, Christenson said.