The transit method requires watching the light output of a star over long periods of time. A transit occurs when the planet crosses in front of its star from earths point of view. Since there is a small object (the planet) now blocking some of the star, it appears to dim a little bit for a while until the planet passes. If we are in a position where that occurs regularly (most paths of planets do not happen to be on the line of sight between earth and their star) we can deduce the period of orbit. From the amount of dimming and the period you can estimate the mass
The appropriate response is the third one. A generator is utilized to enact the control poles which contain radioactive isotopes. Once initiated, these isotopes start an atomic splitting chain response. Water in a cooling tank monitors the rate of response as electrons radiated from the response are encouraged through wires to homes and organizations.
