Because of the following code:

    try
        solution = $(value).find('.detailed-solution')
    catch e
        solution = {}

    if solution.length
        answer_text.push(solution)
    else
        answer_text.push('<p>' + gettext('Answer:') + ' ' + value + '</p>')

When we push solution - it is a `jQuery` object returned by selector `'.detailed-solution'`. In the other case, it is jut a string `'<p>' + gettext('Answer:') + ' ' + value + '</p>'`.