Which preposition to use with unsolved

in Occurrences 3%

And if this were let pass, the argument is yet unsolved in itself; for he that wants Judgement in the liberty of his Phancy, may as well shew the defect of it in its confinement: and, to say truth, he that has judgement will avoid the errors, and he that wants it, will commit them both.

at Occurrences 1%

If so, what mystery, even of Omnipotent wisdom, will remain unsolved at last?

by Occurrences 1%

Mesmer brought from Germany his mysterious revelations in respect of problems as yet unsolved by science, and pretended to cure all diseases around the magnetic battery; the adventurer Cagliostro, embellished with the title of count, and lavishing gold by handfuls, bewitched court and city, and induced Councillor d'Epremesnil to say, "The friendship of M. de Cagliostro does me honor."

for Occurrences 1%

The mystery remained unsolved for that evening; and it was not till some weeks later that the chances of an official enquiry brought us face to face again.

through Occurrences 1%

Vital problems affecting the welfare of the whole country, remaining unsolved through the years, have at last reached an acute stage where they demand solution.

Which preposition to use with  unsolved