Load range C tires on 14" rims are rated at either 1760lbs or 1870lbs each @ 50psi depending on the tire width of either 205 or 215. Consequently, 4 load range C tires on a dual axle trailer would carry a maximum load of 7040 lbs or 7480 lbs, respectively. My previous TT had 205/75/14 load range C tires, a GVWR of 6000 lbs and weighed only 4000 lbs dry. Taking into account tongue weight of 650 lbs I had 1690 extra capacity not utilized on the tires if the trailer was fully loaded with 2000 lbs of cargo which would be nearly impossible to do. Towed that trailer many miles without a problem.
I am not discounting a previous post that the trailer should be easier to pull with a D tire due to the higher 65psi and stronger sidewalls. However, I would make sure that your rim is capable of 65psi and is the proper width.