Looking for errors:
1. Passion is Key or A,B and C are KEYS to xx
2. Simple Present Tense is preferred. ( has long maintained) . If past tense, will take a decision if no other error.
A. her passion for good food, fine wine, and all of life’s other sensual pleasures are
Passion are-wrong Subject Verb Agreement
One passion for attainment ARE ? wrong
B. her passion for good food, fine wine, and all of life’s other sensual pleasures is
Passion is keys? -wrong
One passion can be keys to multiple factors but not a single factor: her attainment to true happiness
C. her passion for good food, for fine wine, and for all of life’s other sensual pleasures were
Passion for A, passion for B and passion for C were( 3 different passions) WAS the KEY to a SINGLE FACTOR
plural verb makes it wrong
The statement is in general fact; simple present is preferred.-wrong
D. good food, fine wine, and all of life’s other sensual pleasures – each a passion of hers – are
A,B and C are KEYS to xx - grammatically correct
Logical :Hold on if E is better?
E. good food, fine wine, and all of life’s other sensual pleasures, all of them were her passions and were
A,B and C, all of them?- wrong sentence construction
All-A,B and C- xx ( could be the right construction)-wrong
(All is one of SANAM pronoun)
Hence D is better choice.