请教一道语法题GWD2-30

Q30:

Most insomnia is not an illness or a
physical condition so much as a symptom of another problem that may simply be a
reaction to certain medications, anxiety about travel, or stress before a
job interview.

                
1. an illness or a physical condition so much as a symptom of
        another problem that may simply be a reaction to certain medications

                
2. an illness or a physical condition so much as symptomatic of
        another problem that may be a simple one, like a reaction caused by
        certain medications

                
3. so much an illness or a physical condition but a symptom of
        another problem that may be as simple as when certain medications cause a
        reaction

                
4. so much an illness or a physical condition, but it is a symptom
        of another problem, maybe a simple one like certain medications causing a
        reaction

                
5. so much an illness or a physical condition but symptomatic of
        another problem, maybe simply a reaction to certain medications

From Longman: It is an idiom

9
            

not so much...as...

used to say that one description of someone or something is less suitable or correct than another:

She was not so much nervous as impatient for the journey to be over