According to the Heisenberg uncertainty principle,which of the following expressions is correct?

What is quantum mechanics? Give its primary information.

Why was a change in the Bohr Model of atom required? Due to which important development$(s)$,was the concept of movement of an electron in an orbit replaced by the concept of probability of finding an electron in an orbital? What is the name given to the changed model of atom?

If the uncertainty in momentum and uncertainty in the position of a particle are equal,then the uncertainty in its velocity would be given by

When uncertainty in position and momentum are equal, then the uncertainty in velocity is

Given below are two statements $:$
Statement $(I):$ It is impossible to specify simultaneously with arbitrary precision,both the linear momentum and the position of a particle.
Statement $(II) :$ If the uncertainty in the measurement of position and uncertainty in measurement of momentum are equal for an electron,then the uncertainty in the measurement of velocity is $\geq \sqrt{\frac{h}{4\pi}} \times \frac{1}{m}$ which simplifies to $\geq \frac{1}{2m} \sqrt{\frac{h}{\pi}}$. In the light of the above statements,choose the correct answer from the options given below $:$