Firstly, U should have provided the options either or LCM value to get the HCF.
because absence of any one of themm cannot solve.
However the concept would be:
HCF is the factor of LCM therefore it would be also the factor of 3780000.
That option would resemble the HCF value.
for example options are : 34 and 20
then 20 would be the HCF as it is a factor of 3780000.