The total number of primary alcohol and primary amine respectively of molecular formula C5H12O and C5H13N.A 8, 8 B 4, 4 C 4, 8 D 8, 4

The molecular formula for primary alcohol is R-CH2-OH and for primary amine is R-CH2-NH2.

For C5H12O (primary alcohol):

1. The longest carbon chain can be 5 carbons long. The OH group can be attached to any one of the 5 carbons. So, there are 5 possibilities.

2. The longest carbon chain can be 4 carbons long. The OH group can be attached to any one of the 4 carbons. But, the fifth carbon can be attached to any one of the 4 carbons in the chain. So, there are 4*4 = 16 possibilities. But, two of these will be duplicates (when the OH group and the fifth carbon are attached to the same carbon in the chain). So, there are 16-2 = 14 possibilities.

3. The longest carbon chain can be 3 carbons long. The OH group can be attached to any one of the 3 carbons. But, the remaining two carbons can be attached in 3 ways (either both to the same carbon, or one each to two different carbons). So, there are 3*3 = 9 possibilities. But, three of these will be duplicates (when the OH group and the two carbons are attached to the same carbon in the chain). So, there are 9-3 = 6 possibilities.

Adding these up, there are 5+14+6 = 25 possibilities. But, some of these will be duplicates (when the OH group and the fifth carbon are attached to the same carbon in the chain). So, the total number of primary alcohols is less than 25. The exact number is difficult to calculate without drawing all the structures, but it is certainly less than 8.

For C5H13N (primary amine):

1. The longest carbon chain can be 5 carbons long. The NH2 group can be attached to any one of the 5 carbons. So, there are 5 possibilities.

2. The longest carbon chain can be 4 carbons long. The NH2 group can be attached to any one of the 4 carbons. But, the fifth carbon can be attached to any one of the 4 carbons in the chain. So, there are 4*4 = 16 possibilities. But, two of these will be duplicates (when the NH2 group and the fifth carbon are attached to the same carbon in the chain). So, there are 16-2 = 14 possibilities.

3. The longest carbon chain can be 3 carbons long. The NH2 group can be attached to any one of the 3 carbons. But, the remaining two carbons can be attached in 3 ways (either both to the same carbon, or one each to two different carbons). So, there are 3*3 = 9 possibilities. But, three of these will be duplicates (when the NH2 group and the two carbons are attached to the same carbon in the chain). So, there are 9-3 = 6 possibilities.

Adding these up, there are 5+14+6 = 25 possibilities. But, some of these will be duplicates (when the NH2 group and the fifth carbon are attached to the same carbon in the chain). So, the total number of primary amines is less than 25. The exact number is difficult to calculate without drawing all the structures, but it is certainly less than 8.

So, the answer is none of the above.