Let the present ages of P, Q & R be P years, Q years and R years respectively.

According to 1^st conditin of question, P + 2Q + R = 59 ………….(1)

According to 2^nd condition of question, 3P + Q + R = 68 ………….(2)

According to 3^rd condition of question, P + 3Q + 3R = 108 …….(3)

From (2), we get

Q + R = 68 – 3P ……………………..(4)

From (3), we get

P + 3 (Q + R) = 108

P + 3 (68 – 3P) = 108 ……………….using (4)

P + 204 – 9P = 108

= 8P = 96

Then, P = 12

P’s present age = 12 yrs.

Hence, Option C is the answer