**Core Concept**
The genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or RNA sequences) into proteins. A codon is a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule. Each codon specifies one of the 20 amino acids that are the building blocks of proteins.

**Why the Correct Answer is Right**
With 4 nucleotides instead of 3, the number of possible codons increases exponentially. Since each position in the codon can be one of the four nucleotides (A, C, G, or T), the total number of possible codons is 4^4 = 256. However, not all of these codons code for amino acids. The standard genetic code allows for 64 possible codons (4^3), but only 20 of these code for amino acids. Assuming that the additional codons code for amino acids in a similar manner to the standard genetic code, we can estimate that up to 256 - 64 = 192 additional amino acids may be formed.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely to be incorrect because it does not take into account the exponential increase in the number of possible codons with 4 nucleotides.
**Option B:** This option is likely to be incorrect because it does not consider the standard genetic code and the number of codons that code for amino acids.
**Option C:** This option is likely to be incorrect because it is too low and does not account for the additional codons that could code for amino acids.

**Clinical Pearl / High-Yield Fact**
In the standard genetic code, each codon specifies one of the 20 amino acids, but some codons code for the same amino acid (synonymous codons). This redundancy allows for errors in DNA replication and translation without affecting the final protein sequence.

**Correct Answer:** D.