will rate thumbs up please help

An unknown compound was found to have the following spectral data: M = 206 and 208 in a 1:1 ratio. IR: 3000-2850 cm '; 1705 cm-1 IH NMR: 1.3 ppm (3H, t); 1.6 ppm (9H, s); 2.2 ppm (2H, 9); 4.8 ppm (IH, s) 13C NMR: 6 total signals: 18 ppm, 21 ppm, 31 ppm, 39 ppm, 56 ppm, 190 ppm (3) a) What does M* = 190 AND 192 in a 1:1 ratio represent and what is a reasonable molecular formula? HINT: Look at IR data also. SHOW YOUR CALCULATIONS. (3) b) What functional group or groups does/do the IR data indicate about the molecule, based on your proposed formula? (3) c) What does 1.3 ppm, 3H, triplet indicate based on integration, splitting pattern, and chemical shift? Write in WORDS. (3) d) What does 1.6 ppm, 9H, singlet indicate based on integration, splitting pattern, and chemical shift? Write in WORDS