Which is the correct choice in each? My choice is 'b' for all four.<br/><br/>1a. mid-to-late 40s<br/>1b. mid to late 40s<br/>1c. mid- to late 40s<br/><br/>2a. low-to-mid 50s<br/>2b. low to mid 50s<br/>2c. low to mid-50s<br/><br/>3a. mid-to-upper 90s<br/>3b. mid to upper 90s<br/>3c. mid- to upper 90s<br/><br/>4a. middle-to-upper 70s<br/>4b. middle to upper 70s<br/>4c. middle- to upper 70s<br/><br/>Thank you