Ukraine is preparing a military response after Russia pounded the country with a massive barrage of missiles, cruise missiles and drones in what officials said was one of the heaviest air attacks in two and a half years of war. Fifteen of Ukraine’s 24 regions were hit in the assault which was directed against Ukraine’s energy sector, Ukrainian Prime Minister Denys Shmyhal said on Telegram on Monday. Authorities put the death toll at seven, with 47 people said to have been injured across the country. Ukrainian President Volodymyr Zelensky said he had discussed Ukraine’s response to the attack w…