$\begin{array}{ccccccccc}Companies& A& B& C& D& E& F& G& H\\ No.ofcompetitors& 1& 3& 6& 4& 7& 3& 3& 6\end{array}$

Since E has 7 competitors ,every other company is its competitor. A has only one competitor,thus only E is its competitor. H and C have 6 competitors each , so , all the companies except A will be their competitors. B AND G have only 3 competitors each , so, they won't have any competitor except E,C and H. To complete this, for the number of competitors for D to be 4, D and F should be each other's competitor.

$\begin{array}{cc}COMPANIES& COMPETITORS\\ A& E\\ B& E,H,C,\\ C& E,B,D,F,G,H\\ D& E,H,C,F\\ E& A,B,C,D,F,G,H\\ F& E,H,C,D\\ G& E,H,C,\\ H& E,C,B,D,F,G\end{array}$

Hence, F has 4 competitors.