Sytnax Error for unexpected argument "min-active-members" ""

I have a tmsh script and I'm getting error "" unexpected argument "min-active-members" "" Can you please help me out in fixing the script with the correct syntax.

create ltm pool pool-a-b-c { members add { nodea-1.2.3.4:1111 { address 1.2.3.4 priority-group 2 } } { nodeb-5.6.7.8:2222 { address 5.6.7.8 priority-group 1 } } min-active-members 1 monitor /Common/tcp_half_open }

Thanks in Advance