He didn't attend the sports meeting . It is __ his leg was burt. A as B because可以说明理由吗？

He didn't attend the sports meeting . It is __ his leg was burt. A as B because
可以说明理由吗？

B because

B。because: 因为这里有It is , 所以要用because才匹配。 如果用as就要去掉前面的it is.