Hiram Bingham, explorer and professor of South American history, first crossed the Andes
Mountains in February 1909, the wettest month of the year, which makes his travels difficult.
a) which makes his travels difficult
b) that had made his travels difficult
c) which should have made his travels difficult
d) because it made his travels difficult
e) making his travels difficult
Can someone help me on this one..?
Looking at the question, you can see that the two events crossing of the Andes mountain and the wettest month which made his travel difficult should be in continuity, i.e. one should follow the other.
a) which makes his travels difficult (makes bring this into present, so can be easily left out because even happened in 1909)
b) that had made his travels difficult (had made his travel difficult, implies that this happened before he crossed the Andes Mountain, makes it absurd)
c) which should have made his travels difficult (We are not contemplating whether wetter month made it difficult, so neglected)
d) because it made his travels difficult (antecedent of "it" is unclear, it can refer to wettest month or to the Andes mountain, so neglected)
e) making his travels difficult (continuous tense after the past, logically follows because it shows the continuity and one event happened after the other, so accepted)