Bunuel
Unless the conservator can find a way to protect the photographs in the archives from light and air, these precious historical documents have deteriorated and will continue to do so both in color and in fine detail.
A. have deteriorated and will continue to do so
THere is no adequate reasoning for changing tense therefore out
B. will continue to deteriorate
The tense and the meaning conveyed are perfect therefore let us hang on to it
C. have been and will continue to deteriorate
THere is no requirement of using past perfect tense when simple future tense can address the same adequately therefore out
D. will continue to deteriorate, as they already have,
'they ' isn't having the right reference therefore out
E. will be deteriorating yet more
'yet' what exactly is the role of the word , for example even though the non violent atrocities are happening against the underprivilaged
the law enforcement hasn't yet taken any action , the possible scenario cases require 'yet' not in our sentence therefore out
THerefore IMO B