$A$ $10 \ W$ electric heater is used to heat a container filled with $0.5 \ kg$ of water. It is found that the temperature of the water and the container rises by $3 \ K$ in $15 \ min$. The container is then emptied,dried,and filled with $2 \ kg$ of oil. The same heater now raises the temperature of the container-oil system by $2 \ K$ in $20 \ min$. Assuming that there is no heat loss in the process and the specific heat of water is $4200 \ J \ kg^{-1} \ K^{-1}$,the specific heat of oil in the same unit is equal to:

• A
  $1.50 \times 10^{3}$
• B
  $2.55 \times 10^{3}$
• C
  $3.00 \times 10^{3}$
• D
  $5.10 \times 10^{3}$