500
                            How does lightning start?
A.  When high winds blow over high voltage wires,
the winds carry the electricity from one place to
another.
B.  The clouds gather solar energy from the sun, and
when the cloud absorbs enough solar energy, it
releases that energy in the form of lightning.
C.  Electric charges build up in the cloud because the
molecules in the cloud rub each other and form a
static charge. Once the charge increases enough,
it travels through the air as lightning.
D.  The humid air that rises from the ground contains
heat, and when all this heat gathers together, the
heat is released in the form of lightning.
                            What is 
C.  Electric charges build up in the cloud because the
molecules in the cloud rub each other and form a
static charge. Once the charge increases enough,
it travels through the air as lightning.