A coordinate bond (also known as a dative bond) is a type of covalent bond in which one atom provides both of the shared electrons. This typically occurs when a species with a lone pair of electrons (Lewis base) donates them to an electron-deficient species (Lewis acid).

Let's analyze the given options:

• A) ${\mathrm{NH}}_3$ (Ammonia): Ammonia contains three N-H covalent bonds. Nitrogen has one lone pair of electrons, but these are not involved in forming a coordinate bond within the ${\mathrm{NH}}_3$ molecule itself.
• B) ${\mathrm{NH}}_4\mathrm{OH}$ (Ammonium Hydroxide): This compound exists in aqueous solution as ${\mathrm{NH}}_4^{+}$ (ammonium ion) and ${\mathrm{OH}}^{-}$ (hydroxide ion). The ammonium ion ${\mathrm{NH}}_4^{+}$ is formed when ammonia ${\mathrm{NH}}_3$ donates its lone pair of electrons to a proton ${\mathrm{H}}^{+}$. This N-H bond formed is a coordinate bond. The structure of ${\mathrm{NH}}_4^{+}$ has one coordinate bond and three covalent bonds.
• C) ${\mathrm{H}}_2\mathrm{O}$ (Water): Water contains two O-H covalent bonds. Oxygen has two lone pairs, but these are not involved in forming a coordinate bond within the ${\mathrm{H}}_2\mathrm{O}$ molecule itself.
• D) $\mathrm{HCl}$ (Hydrogen Chloride): Hydrogen chloride contains one H-Cl covalent bond. There are no coordinate bonds in the $\mathrm{HCl}$ molecule.

Therefore, ${\mathrm{NH}}_4\mathrm{OH}$ (specifically the ${\mathrm{NH}}_4^{+}$ ion) contains a coordinate bond.

Correct Answer: (B)