Identify what each test detects

• Ceric ammonium nitrate test gives a positive result for alcoholic , $-OH$ groups.
• Carbylamine test gives a positive result only for primary amines , $( -NH_2 )$.

Check which amino acid side chains can respond

In peptides, the terminal groups are:

• N-terminus: usually a free amino group
• C-terminus: usually a free carboxyl group

Also, side chains may contain relevant functional groups:

• Serine (Ser): side chain $-CH_2OH$ , $\Rightarrow$ alcohol present
• Lysine (Lys): side chain $-(CH_2)_4NH_2$ , $\Rightarrow$ primary amine present
• Aspartic acid (Asp): side chain $-CH_2COOH$ , no alcohol, no primary amine side chain
• Glutamine (Gln): side chain $-CH_2CH_2CONH_2$ , amide, not a primary amine for carbylamine test

Evaluate each option

Option A: Ser-Lys

• Ser provides an alcohol group , $\Rightarrow$ positive ceric ammonium nitrate test
• Lys provides a primary amino group in side chain , $\Rightarrow$ positive carbylamine test
• Hence, this peptide gives both tests positive.

Option B: Asp-Gln

• Asp has carboxylic acid side chain, no alcohol
• Gln has amide side chain, not primary amine for carbylamine test
• Does not satisfy both tests.

Option C: Gln-Asp

• Same functional groups as option B, only order changed
• Does not satisfy both tests.

Option D: Lys-Asp

• Lys gives primary amine , $\Rightarrow$ carbylamine positive
• Asp has no alcohol group , $\Rightarrow$ ceric ammonium nitrate negative
• Does not satisfy both tests.

Final conclusion

The peptide that gives both positive ceric ammonium nitrate and carbylamine tests is: $\boxed{\text{Ser-Lys}}$

Comparison with stored correct answer

Stored correct answer: A

Derived answer: A

So, the derived answer agrees with the stored correct answer.