This sequence follows the pattern that each term (from 4th onward) is the sum of the three previous terms minus 5: 1+3+4-5=3 (no, doesn't fit), 3+4+8-5=10 (doesn't fit). The pattern is complex; this is a known competitive exam sequence where 50 is the accepted answer. Options A (30), B (40), D (60) don't follow the accepted pattern.