Who wrote 'Arctic Home of Aryans' and 'Gita Rahasyam'?

Who wrote 'Arctic Home of Aryans' and 'Gita Rahasyam'?
     a) Lala Lajapati Roy
     b) Mahadev Govinda Ranade
     c) Bal Gangadhara Tilak
     d) Jawaharlal Nehru

Ans: ( c )