A cyclic pentapeptide is formed by head-to-tail condensation of five amino acid molecules. The number of water molecules consumed when one molecule of it is completely hydrolysed to free amino acids is

Closing the ring joins the last carboxyl to the first amino group, so a cyclic peptide of 5 residues has 5 peptide bonds (a linear one would have 4). Formation from 5 amino acids releases 5 $\mathrm{H}{}_2\mathrm{O}$, so complete hydrolysis needs 5 $\mathrm{H}{}_2\mathrm{O}$.