Not sure, if this SC was already discussed in the forum; I searched for it but did'nt get the link and hence posting it here ..
Soaring television costs accounted for more than half the spending in the presidential campaign of 1992, a greater proportion than it was in any previous election.
- a greater proportion than it was
- a greater proportion than
- a greater proportion than they have been
- which is greater than was so
- which is greater than it has been
Friends, pl help with explanations