Dear Friends,

I was having problems in answering the following question.

On Earth, among the surest indications of sunspot cycles are believed to be the rate
that trees grow, as seen in the rings visible in the cross sections of their trunks.

A. On Earth, among the surest indications of sunspot cycles are believed to be the rate
that trees grow
B. On Earth, among the surest indications of sunspot cycles are, it is believed, the rate of
tree growth
C. On Earth, the rate at which trees grow is believed to be among the surest indications
of sunspot cycles
D. Among the surest indications on Earth of sunspot cycles, believed to be the tree
growth rate
E. Among the surest indications on Earth of sunspot cycles is believed to be the rate at
which trees grow


Please help.

OA after some discussions.

Regards
Deano.