Although introns are not a part of the processed transcript that gets translated, they are important for several reasons. The following statements are made with reference to the possible ways in which introns are crucial to cell survival.

A. They permit the generation of different protein products from the same gene.
B. They may encode miRNAs which modulate the expression of genes.
C. They often encode peptides which play a role in regulating gene expression.
D. They promote export of certain mRNAs through the recruitment of transport proteins by the Exon Junction Complex (EJC).
E. They play a role in mRNA surveillance through the modulation of nonsense-mediated mRNA decay via the Exon Junction Complex (EJC).

Which one of the following options represents the combination of all correct statements?

Correct option is C

Explanation-

Statement A -  They permit the generation of different protein products from the same gene.
True.
This is due to alternative splicing — the presence of introns allows different combinations of exons to be joined, producing isoforms. They are critical for protein diversity.
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Statement B - They may encode miRNAs which modulate the expression of genes.
True.
Some miRNAs are derived from intronic sequences ("mirtrons"). These miRNAs play a regulatory role in gene expression post-transcriptionally.

Statement C - They often encode peptides which play a role in regulating gene expression.
Mostly False (or not well-supported biologically).
While rare cases may exist where retained intronic sequences are translated, introns typically do not encode functional peptides. They are usually non-coding.

Statement D -  They promote export of certain mRNAs through the recruitment of transport proteins by the Exon Junction Complex (EJC).
True.
After splicing, the EJC is deposited near exon-exon junctions and facilitates mRNA export. Thus, splicing of introns indirectly enhances mRNA nuclear export.

Statement E -  They play a role in mRNA surveillance through the modulation of nonsense-mediated mRNA decay via the Exon Junction Complex (EJC).
True.
​Introns help position EJCs, and if a premature stop codon is detected upstream of an EJC, nonsense-mediated decay (NMD) is triggered. This protects cells from producing truncated or harmful proteins.

Since the correct statements are A, B ,D and E 
Therefore , the correct answer is option c — A, B, D, and E