Comparison - GMAT paper test

[Mo2men]

A neutron star, as small as 12 miles in diameter but containing half as much matter as the Sun, has a gravitational force at its surface about 67 billion times greater than that on Earth.

(A) 12 miles in diameter but containing half as much matter as the Sun

(B) 12 miles in diameter but contains half the matter of the Sun

(C) 12 miles in diameter but it contains half as much matter as the Sun

(D) a diameter of 12 miles but containing half as much matter as the Sun's

(E) a diameter of 12 miles but contains half the Sun's matter

OA: A

Dear GMATGuru,

Can you comment help understand OA? 'as much as' should compare tow clauses but here is compares adjective ' containing ........' and 'Sun'. I assumes there is omitted verb in the clause 'the sun contains or does'.

Thanks in advance

[GMATGuruNY]

Dear GMATGuru,

Can you comment help understand OA? 'as much as' should compare tow clauses but here is compares adjective ' containing ........' and 'Sun'. I assumes there is omitted verb in the clause 'the sun contains or does'.

Thanks in advance

OA: A neutron star, as small as 12 miles in diameter but containing half as much matter as the Sun, has a gravitational force at its surface about 67 billion times greater than that on Earth.
The green portion conveys the following meaning:
[A neutron star is] containing half as much matter as the Sun [is containing].
The words in brackets are omitted so that the green portion can serve as a modifier -- a modifier parallel with the preceding blue modifier.