A research participant is required to report as much of a poem as he can remember, immediately after having read the poem once. We would expect the greatest number of recall errors in lines:

A: at the end of the poem.

B: in the middle of the poem.

C: anywhere in the poem.

D: at the beginning of the poem.

B.

Explanation:

Memory errors or recall errors can be defined as those errors that one faces while remembering certain events from the past, etc.

The phenomenon of memory loss in the given passage refers to 'serial position effect.'

According to this effect, when a person is provided with a long list or a long text, he/she tends to forget the list or the text in the middle.

In the given case, a researcher who is required to remember a poem is likely to forget or expect great numbers of recall errors in the middle of the poem.

So, the correct answer is option B.