In the `S_(N)2` reaction of iodide ion with `
(CH_(3))_(2)CHCH_(2)CH_(2)X`, what is the order of decreasing reactivity for the following X substituents ?
I. `X=-OH " " ` , II. `X=CH_(3)CO_(2)^(-)`
III `X=CF_(3) SO_(3)^(-) " " ` ,IV. `X=CCl_(3)CO_(2)^(-)`
A. `I gt II gt III gtIV`
B. `IV gt III gt II gt I`
C. `III gt II gt IV gt I`
D. `III gt IV gt II gt I`