The question asks:

Which of the following will not exist in zwitter ionic form at $\mathrm{pH}=7$?

However, the actual structures/options A, B, C, and D are missing in the prompt. So the specific compounds cannot be evaluated directly.

1. Concept of zwitter ion at $\mathrm{pH}=7$

A compound exists as a zwitter ion when it contains both:

• a basic group that can be protonated, such as $-\mathrm{NH_2} \to -\mathrm{NH_3^+}$
• an acidic group that can be deprotonated, such as $-\mathrm{COOH} \to -\mathrm{COO^-}$

At about neutral pH, common amino acids usually exist as:

$\mathrm{H_3N^+-CHR-COO^-}$

So, any molecule having both an amino group and a carboxylic acid group generally exists significantly in zwitter ionic form near $\mathrm{pH}=7$.

2. What kind of compound will not be zwitterionic?

A compound will not exist as a zwitter ion at $\mathrm{pH}=7$ if it lacks one of the required functionalities, for example:

1. it has no acidic group to form a negative charge, or
2. it has no basic group to form a positive charge, or
3. the acidic/basic strengths are such that zwitterion formation is not possible at pH 7.

Typical examples that do not form zwitter ions at pH 7 are:

• simple amines
• simple carboxylic acids without amino group
• amides like glycinamide $\mathrm{H_2NCH_2CONH_2}$ (amide group is not acidic like $-\mathrm{COOH}$)

3. Limitation in this question

Since options A, B, C, D are blank, it is impossible to derive the exact correct option from the given information alone.

4. Comparison with stored answer

The stored correct answer is D. Because the actual structures are missing, I cannot independently verify it from first principles.

If option D is the one lacking the proper acidic/basic pair needed for zwitterion formation, then D would indeed be correct.

So based on the available data, I can only tentatively accept the stored answer, but this is not a true derivation.