Option(a.),' abrupt', refers to commodity that's going on ‘ exceedingly suddenly and suddenly ’.

 thus, option(a.) is correct as its meaning is synonymous to it of the given word ‘ concise ’.

 Option(b.), ‘ scarce', refers to commodity that's going on ‘ only a really short time before ’.

 thus, option(b.) is inaccurate as its meaning is not synonymous thereto of the given word ‘ concise ’.

 Option(c.), ‘ verbose', refers to commodity ‘ moving outward ’.

 thus, option(c.) is wrong as its meaning is not synonymous therewith of the given word ‘ concise ’.

 Option(d.), ‘ headless', refers to commodity or someone ‘ not having a head or formed without ahead ’.

 thus, option(d.) is inaccurate as its meaning is not synonymous therefore of the given word ‘ concise ’