Answer:
a) solar activity -- sudden eruptions of large bubbles of plasma and magnetic energy
and
d) solar flare -- sudden release of magnetic energy
Explanation:
We can start by eliminating the options that are definitely wrong.
A coronal mass ejection is not a relatively cool spot on surface of the sun, in fact such a spot is a sunspot, while a coronal mass ejection occurs when the magnetic field of the sun emerges as a loop. Thus, both options B and E are incorrect, leaving only A, C, and D. Option C makes no sense, as the sun's gravitational field does not 'churn'. Thus, only options A and D are left. A closer look at A and D reveals they are correct; solar flares are in fact sudden releases of magnetic energy, as seen in this quote from UC Berkeley's website; "Solar flares are caused by sudden changes of strong magnetic fields in the Sun's corona.". And solar activity is a blanket term for the effects of eruptions of plasma and magnetic energy from the sun.
Venus is closer, relatively the same size as the earth and has an atmosphere
If the object's kinetic energy is zero, then due to in multiplication factor, it's momentum will also be equal to zero 'cause the velocity of the object must be Nil
In short, Your Answer would be: "Zero"
Hope this helps!