Answer:
rent expense   200 debit
   prepaid rent       200 credit
--to record expired rent--
Explanation:
Timeline:
<-----//-------//---------------------->
Jan 1st   Jan31th
The amount paid is for six month of rent. So, 1,200 is the value of six month.
So each month is worth 1,200 / 6 = 200
Ad the end of the month we will reduce the prepaid and recognize the rent expense for January