Can you solve this?

I almost did that but I'm struggling to find the mass to put in the equation T=2π√(I/mgl) Where I is MOI, m- mass, g- acc due gravity, l- distance of centre of mass from suspension

I almost did that but I'm struggling to find the mass to put in the equation T=2π√(I/mgl) Where I is MOI, m- mass, g- acc due gravity, l- distance of centre of mass from suspension