Question: Cetalkonium chloride (CKC) is a quaternary ammonium compound of which type of cationic surfactant?
Context: Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+ , R being an alkyl group or an aryl group.  Unlike the ammonium ion (NH4+ ) and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged, independent of the pH of their solution.  Quaternary ammonium salts or quaternary ammonium compounds (called quaternary amines in oilfield parlance) are salts of quaternary ammonium cations. A betaine (BEET-ah-een, ) in chemistry is any neutral chemical compound with a positively charged cationic functional group such as a quaternary ammonium or phosphonium cation (generally: onium ions) which bears no hydrogen atom and with a negatively charged functional group such as a carboxylate group which may not be adjacent to the cationic site.  A betaine thus may be a specific type of zwitterion.  Historically the term was reserved for TMG (trimethylglycine) only.  Biologically, betaine is involved in methylation reactions and detoxification of homocysteine. Guar hydroxypropyltrimonium chloride is an organic compound that is a water-soluble quaternary ammonium derivative of guar gum.  It gives conditioning properties to shampoos and after-shampoo hair care products.  The effects of the cationic charge density, guar concentration in aqueous solution, and treatment time on bleached European hair have been studied.  A mechanical testing method has been successfully applied to determine the efficacy of cationic guars to improve the ease of combing.  The results were confirmed in a shampoo formulation on both virgin and bleached hair. Benzododecinium bromide (systematic name dimethyldodecylbenzylammonium bromide) is a quaternary ammonium compound used as antiseptic and disinfectant (phenol coefficient is 20-30).  It is highly soluble in water and has properties of cationic surfactant. Cetylpyridinium chloride (CPC) is a cationic quaternary ammonium compound used in some types of mouthwashes, toothpastes, lozenges, throat sprays, breath sprays, and nasal sprays.  It is an antiseptic that kills bacteria and other microorganisms.  It has been shown to be effective in preventing dental plaque and reducing gingivitis.  It has also been used as an ingredient in certain pesticides. Cetylpyridinium chloride may cause brown stains between the teeth and on the surface of teeth.  However, these stains can be easily removed by a dental hygienist during a routine check-up. Cetalkonium chloride (CKC) is a quaternary ammonium compound of the alkyl-benzyldimethylammonium chloride family, the alkyl group having a chain length of C16 (16 carbons). Benzethonium chloride, also known as hyamine is a synthetic quaternary ammonium salt.  This compound is an odorless white solid, soluble in water.  It has surfactant, antiseptic, and anti-infective properties, and it is used as a topical antimicrobial agent in first aid antiseptics.  It is also found in cosmetics and toiletries such as mouthwashes, anti-itch ointments, and antibacterial moist towelettes.  Benzethonium chloride is also used in the food industry as a hard surface disinfectant. Dimethyldioctadecylammonium chloride also commonly distearyl dimethyl ammonium chloride is an organic compound classified as quaternary ammonium salt.  The nitrogen center substituted with two methyl groups and two stearyl groups.  The combination of long-chain hydrocarbon groups and the cationic ammonium confers surfactant- or a detergent-like properties.  For professional use only, it can be found in many wares-and-equipment sanitizers as well as cleaner/sanitizer combinations that are standard in the foodservice industry - it was once a major component of fabric softeners, but has been largely phased out because of its low biodegradability.  In household products, it may also be found as an ingredient in cosmetics and hair conditioners in which it is added primarily for its antistatic effects.  It is also used in organic synthesis as a phase transfer catalyst to increase reaction rates in a two-phase organic-water system. Benzalkonium chloride, also known as BZK, BKC, BAC, alkyldimethylbenzylammonium chloride and ADBAC, is a type of cationic surfactant.  It is an organic salt classified as a quaternary ammonium compound.  It has three main categories of use: as a biocide, a cationic surfactant, and as a phase transfer agent.  ADBACs are a mixture of alkylbenzyldimethylammonium chlorides, in which the alkyl group has various even-numbered alkyl chain lengths. Tetramethylammonium chloride is one of the simplest quaternary ammonium salts, with four methyl groups tetrahedrally attached to the central N.  The chemical formula (CH)NCl is often abbreviated further as MeNCl.  It is a hygroscopic colourless solid that is soluble in water and polar organic solvents.  Tetramethylammonium chloride is a major industrial chemical, being used in such processes as hydrofracking.  In the laboratory, it has fewer synthetic chemical applications than quaternary ammonium salts containing longer N-alkyl substituents, which are used extensively as phase-transfer catalysts.
Answer: Benzalkonium chloride