刘某，关某，张某合伙购买房屋，与房地产开发商签订买卖合同，该法律关系中法律主体有(　)。

A、<p><span style="font-family: \'Microsoft YaHei\'; font-size: 13px; ">房地产开发商 </span></p>

B、<p><span style="font-family: \'Microsoft YaHei\'; font-size: 13px; ">刘某</span></p>

C、<p><span style="font-family: \'Microsoft YaHei\'; font-size: 13px; ">关某 </span></p>

D、<p><span style="font-family: \'Microsoft YaHei\'; font-size: 13px; ">张某</span></p>

A、<p><span style="font-family: 'Microsoft YaHei'; font-size: 13px; ">房地产开发商 </span></p>

B、<p><span style="font-family: 'Microsoft YaHei'; font-size: 13px; ">刘某</span></p>

C、<p><span style="font-family: 'Microsoft YaHei'; font-size: 13px; ">关某 </span></p>

D、<p><span style="font-family: 'Microsoft YaHei'; font-size: 13px; ">张某</span></p>