问题如下：
The birth rate of Country X will decrease and aging population is growing, immigration policies in the Country X are too restrictive. The growth rate of potential GDP of Country X will:
选项：
A. decrease
B. increase
C. unchanged.
解释：
A is correct.
考点：Factors Favoring and Limiting Economic Growth
解析：根据题干描述，国家X的老龄化严重，出生率低，移民政策严格，说明将来的劳动力会下降，因此潜在GDP增长率也会降低。
应该加上资本和技术条件不变为前提条件
