The electric field is defined as $\vec{E}=\lim\limits_{q_0 \rightarrow 0} \frac{\vec{F}}{q_0}$ where $q_0$ is the test charge and $\vec{F}$ force on $q_0$ due to the source charge. The meaning of $\lim\limits_{q_0 \rightarrow 0}$ is:

The source charge must remain at its original location and its electric field is not affected

The correct answer is Option (1) → The source charge must remain at its original location and its electric field is not affected