The correct answer is: B. 1 Newton metre
A joule (J) is a unit of energy in the International System of Units (SI). It is defined as the work done by a force of one newton (N) acting over a distance of one metre (m).
A newton (N) is the SI unit of force. It is defined as the force that, when applied to a mass of one kilogram (kg), gives it an acceleration of one metre per second squared (m/s^2).
A metre (m) is the SI unit of length. It is defined as the distance that light travels in a vacuum in 1/299,792,458 of a second.
A kilogram (kg) is the SI unit of mass. It is defined as the mass of the International Prototype Kilogram (IPK), which is a cylinder of platinum-iridium alloy that is kept at the International Bureau of Weights and Measures (BIPM) in Sèvres, France.
A dyne (dyn) is a unit of force in the CGS system of units. It is defined as the force that, when applied to a mass of one gram (g), gives it an acceleration of one centimetre per second squared (cm/s^2).
Therefore, one joule is equivalent to one newton metre.