Given A={1,2,{3,4},5}(i) The statement {3,4}⊂A is incorrect because 3∈{3,4}; however, 3∈/A.(ii) The statement {3,4}∈A is correct because {3,4} is an element of A.(iii) The statement {{3,4}}⊂A is correct because {3,4}∈{{3,4}} and {3,4}∈A.(iv) The statement 1∈A is correct because 1 is an element of A.(v) The statement 1⊂A is incorrect because an element of a set can never be a subset of itself.(vi) The statement {1,2,5}⊂ A is correct because each element of {1,2,5} is also an element of A.(vii) The statement {1,2,5}∈A is incorrect because {1,2,5} is not an element of A.(viii) The statement {1,2,3}⊂A is incorrect because 3∈{1,2,3}; however, 3∈/A.(ix) The statement ϕ∈A is incorrect because ϕ is not an element of A.(x) The statement ϕ⊂A is correct because ϕ is a subset of every set.(xi) The statement {ϕ}⊂A is incorrect because ϕϵ{ϕ}; however, ϕ∈/A.