whAt is this pAssAgE mAinly ABout
A．DEmonstrAting thE sErious wEAthEr ConDition ArounD lAkE ChAD.
B．introDuCing pEoplE's ACtivity ArounD lAkE ChAD.
C．AnAlyzing oF thE FACtors thAt CAusE wAtEr DECrEAsEs in lAkE ChAD.
D．introDuCing sCiEntists' work ABout wAtEr ConDition in lAkE ChAD.