#include &lt;iostream&gt;     #include &lt;algorithm&gt;    #include &lt;vector&gt;    using namespace std;    int main &#40;&#41;    &#123;        int first&#91;&#93; = &#123;5, 10, 15, 20, 25&#125;;        int second&#91;&#93; = &#123;50, 40, 30, 20, 10&#125;;        vector&lt;int&gt; v&#40;10&#41;;        vector&lt;int&gt; :: iterator it;        sort &#40;first, first + 5&#41;;        sort &#40;second, second + 5&#41;;        it = set_union &#40;first, first + 5, second, second + 5, v.begin&#40;&#41;&#41;;          v.resize&#40;it-v.begin&#40;&#41;&#41;;        for &#40;it = v.begin&#40;&#41;; it != v.end&#40;&#41;; ++it&#41;            cout &lt;&lt; ' ' &lt;&lt; *it;        cout &lt;&lt; '\n';        return 0;    &#125;
A. 5 10 15
B. 20 25 30
C. 40 50
D. All of the mentioned
Answer:A
#include &lt;iostream&gt;     #include &lt;algorithm&gt;    #include &lt;vector&gt;    using namespace std;    int main &#40;&#41;    &#123;        int first&#91;&#93; = &#123;5, 10, 15, 20, 25&#125;;        int second&#91;&#93; = &#123;50, 40, 30, 20, 10&#125;;        vector&lt;int&gt; v&#40;10&#41;;        vector&lt;int&gt; :: iterator it;        sort &#40;first, first + 5&#41;;        sort &#40;second, second + 5&#41;;        it = set_union &#40;first, first + 5, second, second + 5, v.begin&#40;&#41;&#41;;          v.resize&#40;it-v.begin&#40;&#41;&#41;;        for &#40;it = v.begin&#40;&#41;; it != v.end&#40;&#41;; ++it&#41;            cout &lt;&lt; ' ' &lt;&lt; *it;        cout &lt;&lt; '\n';        return 0;    &#125;
A. 5 10 15 B. 20 25 30 C. 40 50 D. All of the mentioned
Explanation:In this kind of style algorithm, We are finding the elements in the both the vector by using set_union function.