An ongoing archaeological controversy surrounds the question of the da

An ongoing archaeological controversy surrounds the question of the date of the abandonment of the old city of Jericho. In the 1930s the site was excavated by the archaeologist John Garstang, who discovered the remains of a network of collapsed walls, which he dated at about 1400 BC, the time he believed the Israelites were on their conquest, leading him to conclude that the city had fallen in war. In 1950, another archaeologist, Kathleen Kenyon, dated the most recent of Jericho's walls at 2300 BC. Kenyon found no evidence of defensive structures that could confirm Garstang's claims that Jericho had been destroyed by the Israelites in the 15th century BC. In fact, she concluded that Jericho had lain in ruins for centuries before the Israelites arrived.

Which of the following, if true, provides the best additional support for Garstang's theory about the date of the abandonment of Jericho?

A The oldest walls found at the site, along with a number of houses and courtyards, had been constructed over 10,000 years ago, during the Neolithic age.
Out of scope

B An abundance of pottery located at the site coincides with other local pottery common to the 15 th century BC.
Since the pottery common to 15th century BC has been found at the site, it strengthens that the pottery was of 15 century BC and thus there was civilization in 15 century BC.. CORRECT

C The walls of Jericho had been repaired and rebuilt at least seventeen times, probably following damage caused by earthquakes.
Does not give any dates to these reconstruction

D Carbon-14 testing of a sample of charcoal found on the site indicated a date of 1800 BC.
Does not do much but weakens it slightly, if anything

E Earlier archaeologists who hoped to confirm the biblical story of the Israelites' conquest of Jericho concluded that the city had been unoccupied at the time such conquest would have occurred.
Again would weaken and not strengthen

B
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Conc: there was no civilization at the time Israelis arrived.
+ B : Abundance of pottery similar to that of 15th century indicates that there had been a civilization at the time Israelis came.
Hence undermining Jerico's claim of city laid in ruin for centuries before Israelis arrived.
Correct me if my understanding of the argument is wrong.

Found this quite tough and had to reread couple if times - also maybe I was fatigued. On re-reading realised this was actually quite an easy question if we read the argument carefully (which is the case with pretty much all CR questions)

Coming back to the question, the argument says archaeologist Garstang dated the site to be 1400 BCE old. 20 years later another archaeologist Kenyon came and said the site was actually much older - dating it to 2300 BCE. Question stem asks us to support Garstang's claim of 1400 BCE.

If we understand this, Option B becomes easy choice. If Garstang dated the site to 1400 BCE and if we find pottery that was known to be common back in 15th Century at the site - we can safely say that Jericho was still being inhabited in the 15th Century and was probably abandoned sometime during 14000 BCE but definitely not earlier than that (2300 BCE as Kenyon claims).

A bit lengthy but a crisp question indeed.
B) is in fact correct because to strengthen garstang's point we need to weaken kenyon's conclusion that civilization ended long before israelite takeover and B) proves there was a civilization long after what kenyon thought to be the actual abandonment of jericho.
Additional evidence are technically inference based but it helps to think in terms of strengthen and weaken in some of them.