20 weeks. Previous history of molar pregnancy. Large (>6cms) theca lutein cysts. From the above list it is clear that option "a" is correct. Coming on to option "d" i.e. Presence of bilateral theca luteum cyst "Monti and colleagues (1988) repoed that gestational trophoblastic neoplasia was more likely in women with theca-lutein cysts, especially if bilateral.- (i.e. option "d" is correct). So that leaves us with 2 options 'b' and 'c' As far as uterine size larger than 16 weeks is concerned. According to Dutta p 197 - Size of uterus > 20 weeks is considered as a risk factors and not 16 weeks. but according other books excessive uterine enlargement is one of the risk factor. As far as thyrotoxicosis is concerned I did not get any literature regarding, it being one of the risk factors. So, option 'c' is the answer of choice.">