Which British passenger ship was torpedoed by German submarine on March 28 1915?

the British passenger ship called the Lusitania was sunk by a German u-boat on May 7, 1915 a couple months after Germany warned that any ship venturing through the 'war zone' would be sunk. The ship contained approximately 1200 passengers and of that 1200 passengers 128 were Americans.

The British steamship Falaba was torpedoed and sunk by a German submarine on March 28, 1915, the date specified in the question, and slightly earlier than the sinking of the Lusitania on May 7, 1915.