请教OG 12---67

xingxc11

Affording strategic proximity to the Strait of Gibraltar,
Morocco was also of interest to the French throughout
the first half of the twentieth century because they
assumed that if they did not hold it, their grip on
Algeria was always insecure.
(A) if they did not hold it, their grip on Algeria was always insecure
(B) without it their grip on Algeria would never be secure
(C) their grip on Algeria was not ever secure if they did not hold it
(D) without that, they could never be secure about their grip on Algeria
(E) never would their grip on Algeria be secure if they did not hold it
答案是B 请牛牛们帮忙分析一下

balapupu

A，我觉得IF从句，因该要用虚拟语气，而且这个Insecure 表达不如 not secure 准确。
C同A，虚拟语气。
D，that 无指代
E“ would their grip on Algeria ”位置不对