context: On 24 March 1879, Tesla was returned to Gospić under police guard for not having a residence permit. On 17 April 1879, Milutin Tesla died at the age of 60 after contracting an unspecified illness (although some sources say that he died of a stroke). During that year, Tesla taught a large class of students in his old school, Higher Real Gymnasium, in Gospić.
question: నికోలా సోదరుడు ఏ కారణాల వల్ల మరణించాడని కొన్ని వర్గాలు చెబుతున్నాయి?
answers: a stroke