Which replacement corrects the spelling error in this sentence?
When my aunt sent a postcard from Australia to my sister, whose
postcard collection is enormous, its affect on her was one of sheer joy.
A. When my aunt sent a postcard from Australia to my sister, whose
postcard collection is enormous, its affect on her was won of
sheer joy.
B. When my aunt sent a postcard from Australia to my sister, who's
postcard collection is enormous, its affect on her was one of
sheer joy.
C. When my aunt sent a postcard from Australia to my sister, whose
postcard collection is enormous, its effect on her was one of
sheer joy
D. When my aunt sent a postcard from Australia to my sister, whose
postcard collection is enormous, it's affect on her was one of
sheer joy.