Paul made the following promises:

(a) to give $1,000 to Eve, his secretary, for having worked during her lunch hour during the last two months;

(b) to pay the newspaper delivery man $10 a month, if he delivers the paper before 8 am;

(c) to give his exercise machine to Thomas if Thomas collects it from the garage.

To accept part-payment of $900 dollars in full settlement of $1000 debt owed to him by Jenny.

(e) To accept part-payment of $900 dollars and one peppercorn in full settlement of $1000 debt owed to him by Jenny.

(f) To accept part-payment of $900 dollars and in full settlement of $1000 debt which he thinks is owed to him by Jenny. Jenny thinks the actual amount owed is $900.

(g) To accept $900 from Henry in full settlement of a $1000 debt which Jenny owed to Paul.

Which promises are enforceable?