We have to take C, though with a pinch of salt. Because in appositive modifications, the modified is supposed to be touching the comma. Here in C, there is an unnecessary intrusion of the phrase, “at the time”, which is a worry . Take the following case;
Architects and stonemasons,
huge palace and temple clusters were built by the Maya without benefit of the wheel or animal transport.(A) huge palace and temple clusters were built by the Maya without benefit of the wheel or animal transport
(B) without the benefits of animal transport or the wheel, huge palace and temple clusters were built by the Maya
(C) the Maya built huge palace and temple clusters without the benefit of animal transport or the wheel
(D) there were built, without the benefit of the wheel or animal transport, huge palace and temple clusters by the Maya
(E) were the Maya who, without the benefit of the wheel or animal transport, built huge palace and temple clusters
Immediately after architects and stonemasons, which is an appositive modifier, you are supposed place the Maya, which is the modified noun. That is why C is right. On the contrary, E is rejected because of the awkward intrusion of the verb ‘were’ after the comma.
However, what I wish to point out is that the original example, after which this question is modeled, avoids that pitfall wonderfully. That is where this post has slightly skidded. Look at this.
In June of 1987, The Bridge of Trinquetaille, Vincent van Gogh's view of an iron ridge over the
Rhone sold for $20.2million and it was the second highest price ever paid for a painting at auction.
A: Rhone sold for $20.2million and it was
B: Rhone, which sold for 20.2million, was
C: Rhone, was sold for 20.2million,
D: Rhone was sold for 20.2million, being
E: Rhone, sold for 20.2million, and was
Please note that the value is modified by the appositive -
the second highest price ever paid for a painting at auction- , immediately after comma. The choice is obviously C here. This is where it differs from the given text in the current topic.