The contact force is indeed caused by "Contact".
Air resistance is basically a type of friction, which is apparently present providing two object contact.
The rest selections are all interaction force, which is not necessarily caused by contact.
Answer:
The angle it subtend on the retina is
Explanation:
From the question we are told that
The length of the warbler is 
The distance from the binoculars is 
The magnification of the binoculars is 
Without the 8 X binoculars the angle made with the angular size of the object is mathematically represented as



Now magnification can be represented mathematically as

Where
is the angle the image of the warbler subtend on your retina when the binoculars i.e the binoculars zoom.
So

=> 

Generally the conversion to degrees can be mathematically evaluated as

Answer:
The magnification is -6.05.
Explanation:
Given that,
Focal length = 34 cm
Distance of the image =2.4 m = 240 cm
We need to calculate the distance of the object

Where, u = distance of the object
v = distance of the image
f = focal length
Put the value into the formula



The magnification is



Hence, The magnification is -6.05.