Answer:
2nd Option
Explanation:
Austria Hungary was upset at the Serbians because of the incident in Sarajevo. As a result, the Austrians went to Germany for help, which was known as the Blank Check, that Germany would aid Austria-Hungary if the Russians intervened. After 1 month, Austro-Hungary declared on Serbia, which caused Russia to declare on Austro-Hungary, which caused Germany to declare on Russia, which caused France to declare on Germany, and the rest is known.
Russia was historically allied with the Serbians, helping them numerous times against the Ottomans, so it definitely couldn't be the first option. Italy and Germany were actually on good terms, it was only the Austro-Hungarians that the Italians disliked. I don't understand 'Great Britain invited French' but yes, the British did ally with the french.
