Sentence Correction

1.The period when the great painted caves at Lascaux
and Altamira were occupied by Upper Paleolithic
people has been established by carbon-14 dating, but
what is much more difficult to determine are the
reason for their decoration, the use to which primitive
people put the caves, and the meaning of the
magnificently depicted animals.
(A) has been established by carbon-14 dating, but
what is much more difficult to determine are
(B) has been established by carbon-14 dating, but
what is much more difficult to determine is
(C) have been established by carbon-14 dating, but
what is much more difficult to determine is
(D) have been established by carbon-14 dating, but
what is much more difficult to determine are
(E) are established by carbon-14 dating, but that
which is much more difficult to determine is
ans is b... why not a what about the flip ...inversion of the subject.y arent we using it here?




2.Teratomas are unusual form of cancer because they
are composed of tissues such as tooth and bone not
normally found in the organ in which the tumor
appears.
(A) because they are composed of tissues such as
tooth and bone
(B) because they are composed of tissues like tooth
and bone that are
(C) because they are composed of tissues, like tooth
and bone, tissues

(D) in that their composition, tissues such as tooth
and bone, is
(E) in that they are composed of tissues such tooth
and bone, tissues

ans is e
why is d wrong??




3.One view of the economy contends that a large drop
in oil prices should eventually lead to lowering
interest rates, as well as lowering fears about inflation
a rally in stocks and bonds, and a weakening of the
dollar.

(A) lowering interest rates, as well as lowering fears
about inflation,
(B) a lowering of interest rates and of fears about
inflation,
(C) a lowering of interest rates, along with fears
about inflation,
(D) interest rates being lowered, along with fears
about inflation,
(E) interest rates and fears about inflation being
lowered, with

ans is c..
what about b.. why is it wrong?






4.Because the Earth's crust is more solid there and thus
better able to transmit shock waves, an earthquake of
a given magnitude typically devastates an area 100
times greater in the eastern United States than it does
in the West.

(A) of a given magnitude typically devastates an area
100 times greater in the eastern United States
(B) of a given magnitude will typically devastate 100
times the area if it occurs in the eastern United
States instead of the West

(C) will typically devastate 100 times the area in the
eastern United States than one of comparable
magnitude occurring in the West

(D) in the eastern United States will typically
devastate an area 100 times greater than will a
quake of comparable magnitude occurring in the
West\
(E) that occurs in the eastern United States will
typically devastate 100 times more area than if it
occurred with comparable magnitude in the West


whats wrong with E? dont we use times and more together??




i am jus starting up with gmat thing ,so please dont expect intelligent questions..