Explanation:

Correct Answer is (b).The original sentence is erroneous.
Reason: Usage of the phrasal verb 'take up' which means ‘to start doing something regularly as a habit, job, or interest ' is inappropriate in this sentence.
'Take for' which means ‘believe mistakenly’ would be suitable in this context. The phrase ‘take for granted’ means ‘fail to properly appreciate someone or something, especially as a result of overfamiliarity’.
E.g.: The boss takes us for granted, but if we weren't here, this whole company would collapse.
Hence ‘take for’ should be used in place of ‘take up’ to make the sentence grammatically and contextually correct.
Among the given choices, only option B replaces the given bold part most appropriately.The sentence after replacement becomes:
We need to find ways to survive the grief and the loss of so many things we currently take for granted.Option B is hence the correct answer.