For each of the numbered claims below, there is exactly one lettered claim that is equivalent. Identify the equivalent claim for each item. ISome lettered claims are equivalent to more than one...

For each of the numbered claims below, there is exactly one lettered claim that is equivalent. Identify the equivalent claim for each item. ISome lettered claims are equivalent to more than one numbered claim, to it will be neces-sary to use some letters more than once.)
1. Oil prices will drop if the OPEC countries increase their production. 2. Oil prices will drop only if the OPEC countries increase their production. 3. Neither will oil prices drop, nor will the OPEC countries increase their production. 4. Oil prices cannot drop unless the OPEC countries increase their production. 5. The only thing that can prevent oil prices dropping is the OPEC countries' increasing their production. 6. A drop in oil prices is necessary for the OPEC countries to increase their production. 7. All it takes for the OPEC countries to increase their production is a drop in oil prices.