[tex]m\angle A=m\angle F=90^o\\\\m\angle B=m\angle G=90^o\\\\m\angle C=m\angle H=135^o\\\\m\angle D=m\angle J=?\\\\m\angle F+m\angle G+m\angle H+m\angle J=360^o\\90^o+90^o+135^o+m\angle J=360^o\\315^o+m\angle J=360^o\\m\angle J=360^o-315^o\\m\angle J=45^o\\\\Answer:\boxed{A}[/tex]
