Statement-I : Tertiary butyl bromide is highly reactive towards ${\text{SN}}^{\text{1}}$  reaction.
Statement-II : Tertiary butyl carbocation is stabilized by hyperconjugation. 
 

Statement I is correct but statement II is incorrect. 

Statement I is incorrect but statement II is correct. 

Both statement I and statement II are incorrect. 

Both statement I and statement II are  correct.