Answer:
using more wire loops in the solenoid
Step-by-step explanation:
Here we know that rate by Faraday's law of electromagnetism
![EMF = -(d\phi)/(dt)](https://img.qammunity.org/2019/formulas/physics/high-school/o6m6x6p8hfsa03kys7brfzbx40hhzodjdu.png)
Now for solenoid we know that
![EMF = - L(di)/(dt)](https://img.qammunity.org/2019/formulas/physics/high-school/lkblg2s6ktlj79fh1iafu5oeh737rxbp5c.png)
now this EMF of induces need to be increased so here we need to increase
1). By increasing the self inductance(L) of the solenoid coil
2). By increasing the rate of change in flux in the coil by moving it fast
Now here inductance is increased by increasing number of turns in the coil
So here correct answer should be related to the more number of loops of the coil which will increase the electric current in the solenoid