After the announcement that London would host the 2012 Olymp

[BTGmoderatorAT]

After the announcement that London would host the 2012 Olympics, the Olympic Committee revealed that Paris had been in competition with London much longer than Madrid.

A) been in competition with London much longer than Madrid
B) competed with London much longer than Madrid
C) been in competition with London much longer than had Madrid
D) competed with London much longer than had Madrid
E) been in competition much longer with London than Madrid

Confused between options B and D? Can any experts help?

[GMATGuruNY]

Confused between options B and D? Can any experts help?

If a comparison allows for more than one logical interpretation, eliminate the answer choice.

B: Paris had competed with London much longer than Madrid
Interpretation 1: Paris had competed with London much longer than Madrid [had competed with London].
Interpretation 2: Paris had competed with London much longer than [Paris had competed with] Madrid.
Since both interpretations are logical, eliminate B.

D: Paris had competed with London much longer than had Madrid.
Here, the verb in blue allows for only ONE logical interpretation:
Paris had competed with London much longer than had Madrid [competed with London].