Well really, it could not be both A and B, as option B contains the world 'Only' which means it can not (depending on the context) be put with other options, so that rules D out, low levels of second hand smoke can still be harmful, it is even listed on the National Cancer Institute
A)saliva
C) bacteria
E) food particles
Answer:
don't think about stuff to much
An X-ray (as well as a surgical intervention) is recommended when a fractured clavicule belongs to an adult ( or almost adult). For children ( depending on the age group) is only recommended when it's not an open break and the need for a surgical intervention needs to be assesed