Answer:

Explanation:
Generally the workdone in moving the proton is mathematically represented as

Where 
So

Here
is the velocity at A with value 50 m/s
So


Also

Here
is the velocity at A with value 
=> 
=>
So


Now this workdone is also mathematically represented as

So

Here 
So


Generally proton movement is in the direction of the electric field it means that 
So

Answer: The angle between the wire segment and the magnetic field 66.42°
Explanation:
Please see the attachment below
1. I think is letter b.
2. I thinks it's letter c.