Relative And Conjunction

1- St. John the Divine and St. Patrick's Cathedral, both ........................................ are in New York, are among the biggest cathedrals in North America ..................................... were built in European style.

a- which / where

b- of which / that

c- of that / which

d- in which / that

e- where / where

My answer is B

2- Carbon is ................................................. common and adaptable element, ........................................ it even has its own branch of science, known as organic chemistry.

a- neither / nor

b- either a / or

c- not only / and

d- such a / that

e- so much / that

My answer is D