“Olivia” (11:30 a.m., Nickelodeon): She’s a little piglet, but never mind that.

“Olivia” (11:30 a.m., Nickelodeon): She’s a little piglet, but never mind that. Olivia gets things done, has fun adventures, and has loads of friends. No wonder her books are a hit with the preschool set. Now “Olivia” comes to Nickelodeon weekdays starting Monday at 11:30 a.m. Brought to the screen by computer-generated animation, 6 3/4-year-old Olivia starts things off by razzing her younger brother Ian for being too short, then grows concerned that one day he might tower over her. What choice does she have but to try to keep him from growing? After all, no little brother should be bigger than his big sister! A series that deals with pressing issues such as, “If I didn’t have to go to school anymore, would I still have to take a bath?” — this show is adorable.

“The Bachelor” (8 p.m., ABC): On “The Bachelor,” six of the remaining contestants accompany hunky Jason to the set of “General Hospital.” As if they didn’t have a little soap opera of their own going on.

“American Experience” (9 p.m., PBS): The 21st season of “American Experience” opens with a profile of J. Robert Oppenheimer. He’s the guy who led America’s development of the atomic bomb and later had his security clearance revoked due to his association with communists during the 1930s.

“Trust Me” (10 p.m., TNT): If you liked Eric McCormack in “Will & Grace” and Tom Cavanagh in “Ed,” you just might love this witty new drama series, which teams them up in their return to prime time. They play Mason and Conner, two best friends working as partners at a highly regarded Chicago ad agency (Think “Mad Men” without the smoke and 1960s-style nostalgia). Their tight bond, however, is put to the test when Mason, the more responsible and committed of the two, is named the agency’s creative director and thus becomes Conner’s boss. Monica Potter (“Boston Legal”) also stars. The series opener airs right after a new episode of “The Closer.”