Which of the following options is correct?
1 gf = ______
A) 250 N
B) 980 dyne
C) 56 dyne
D) All

Hint: The gf stands for the unit gram-force. It is related to the gravitational force experienced by an object of 1-gram mass.

Formula used: In this solution, we will use the following formula:
Weight of an object: $W = mg$ where $m$ is the mass and $g$ is the gravitational acceleration

Complete step by step answer:
The gram-force is a metric unit of the measurement of force (gf). The gram-force is equal to a mass of one gram multiplied by the standard acceleration due to gravity on Earth’s surface, which is defined as roughly $9.8m/{s^2}$.
Then one gram-force is equal to
$1\,gf = 0.001 \times 9.8\,m/{s^2}$
$ \Rightarrow 1\,gf = 0.0098\,{\text{N}}$
Since we know that $1\,{\text{N = 1}}{{\text{0}}^6}\,{\text{dyne}}$, we can write
$1\,gf = 980\,{\text{dyne}}$

Hence the option (B) is correct.

Additional information: The gram-force is a non-standard unit of force. It is a non-standard unit and is classified as a unit that is not accepted by the SI units system. They had been used in low-precision measurements of force before the General Conference on Weights and Measures deicide that the gravitational acceleration was roughly $9.8m/{s^2}$. Before this decision, it was widely used in much of the world and it is still in use for some purposes. For example, it is used for the tension of bicycle spokes when designing a tire, for informal references to pressure in kilograms per square which is the technical atmosphere at and very close to 1 bar, for the force applied in draw weight of bows in archery events as well. However more standard units of force such as Newton or dyne are always preferred more in the scientific community.

Note: In such questions, we often have to convert the units to all the different units mentioned in the options. For that purpose, we should be familiar with the inter-conversions of basic mechanical quantities of motion such as force, acceleration, distance, etc.