---一道抽代的题,必有重谢!Uptoisomorphism,howmanyadditiveabeliangroupsGoforder16havethepropertythatx+x+x+x=0foreachxinA.0B.1C.2D.3E.5

Question

--- 一道抽代的题,必有重谢!
Up to isomorphism,how many additive abelian groups G of order 16 have the property that x+x+x+x=0 for each x in
A.0 B.1 C.2 D.3 E.5

Answer 1

G1=C2⊕C2⊕C2⊕C2.
G2=C2⊕C2⊕C4.
G3=C4⊕C4.
So the answer is D.