By a writing, Oner leased his home, Blackacre, to Tenn for a term of three years, ending December 31 of last year, at the rent of $1,000 per month. The lease provided that Tenn could sublet and assign. Tenn lived in Blackacre for one year and paid the rent promptly. After one year, Tenn leased Blackacre to Agrit for one year at a rent of $1,000 per month. Agrit took possession of Blackacre and lived there for six months but, because of her unemployment, paid no rent. After six months, on June 30 Agrit abandoned Blackacre, which remained vacant for the balance of that year. Tenn again took possession of Blackacre at the beginning of the third and final year of the term but paid Oner no rent. At the end of the lease term, Oner brought an appropriate action against both Tenn and Agrit to recover $24,000, the unpaid rent. In such action Oner is entitled to a judgment 
against Tenn individually for $24,000, and no judgment against Agrit.  against Tenn individually for $18,000, and against Agrit individually for $6,000.  against Tenn for $12,000, and against Tenn and Agrit jointly and severally for $12,000.  against Tenn individually for $18,000, and against Tenn and Agrit jointly and severally for $6,000. 
Question: By a writing, Oner leased his home, Blackacre, to Tenn for a term of three years, ending December 31 of last year, at the rent of $1,000 per month. The lease provided that Tenn could sublet and assign. Tenn lived in Blackacre for one year and paid the rent promptly. After one year, Tenn leased Blackacre to Agrit for one year at a rent of $1,000 per month. Agrit took possession of Blackacre and lived there for six months but, because of her unemployment, paid no rent. After six months, on June 30 Agrit abandoned Blackacre, which remained vacant for the balance of that year. Tenn again took possession of Blackacre at the beginning of the third and final year of the term but paid Oner no rent. At the end of the lease term, Oner brought an appropriate action against both Tenn and Agrit to recover $24,000, the unpaid rent. In such action Oner is entitled to a judgment 
A. against Tenn individually for $24,000, and no judgment against Agrit. 
B. against Tenn individually for $18,000, and against Agrit individually for $6,000. 
C. against Tenn for $12,000, and against Tenn and Agrit jointly and severally for $12,000. 
D. against Tenn individually for $18,000, and against Tenn and Agrit jointly and severally for $6,000. 
Answer: