Will Fernandinho start in City’s defence again? Walker or Cancelo? Who starts left-back for Man Utd? And Will Mason Greenwood get the nod again? Ahead of the Manchester derby, live on Saturday Night Football on Sky Sports Premier League, we run through the main selection dilemmas facing Pep Guardiola and Ole Gunnar Solskjaer.With City desperate to close the gap on Liverpool at the top of the Premier League, and neighbours United trying to save their own season, these conundrums could have a massive impact at the Etihad… Premier League Table | Fixtures | Top scorersWatch Sky Sports now from £18 a month Manchester Derby Get the Premier League channel and get another Sky Sports channel completely free, now just £18 extra a month. Find out more. Manchester CityThe Fernandinho, Stones, Otamendi conundrum Guardiola will not play John Stones and Nicolas Otamendi together in the centre of City’s defence – the pair have not played together since the 3-2 defeat by Norwich, while Otamendi himself has only played one Premier League minute since the 2-0 defeat by Wolves.When City thrashed United 5-1Jesus: I must try to match AgueroCity’s defensive performances in those two games seemed to be the straw that broke…