Answer:
B) 5mm, 3mm, 7mm
Explanation:
Triangles can only be formed when the sum of each two sides of the triangle is greater than the other side.
A.


<-
Because
, ∴ Option A cannot form a triangle.
B.


Because all combinations satisfy, ∴ Option B can form a triangle.
C.


<-
Because
, ∴ Option C cannot form a triangle.
D.
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
<-
Because
, ∴ Option D cannot form a triangle.
Hope this helps :)