[Yksrep]

If anyone stumbles upon this Post there is the working code.

--parent frame 
local frame = CreateFrame("Frame", "TestFrame", ParentUI) 
frame:SetSize(400, 200) 
frame:SetPoint("CENTER") 
local texture = frame:CreateTexture() 
texture:SetAllPoints() 
texture:SetTexture(0,0,0,0) 
frame.background = texture 


local button = CreateFrame("CheckButton", "ButtonA", TestFrame, "UIPanelButtonTemplate")
button:SetText("ButtonA")
button:SetPoint("LEFT",0,0)
button:SetWidth(120)
button:SetHeight(50)
button:SetScript("OnClick", 
  function()
    ButtonA:SetChecked()
  end);

local button = CreateFrame("CheckButton", "ButtonB", TestFrame, "UIPanelButtonTemplate")
button:SetText("ButtonB")
button:SetPoint("CENTER",0,0)
button:SetWidth(120)
button:SetHeight(50)
button:SetScript("OnClick", 
  function()
    ButtonB:SetChecked()
	if ButtonA:GetChecked() and ButtonB:GetChecked() then
	ButtonC:Show()
	end
  end);

local button = CreateFrame("CheckButton", "ButtonC", TestFrame, "UIPanelButtonTemplate")
button:SetText("ButtonC")
button:SetPoint("RIGHT",0,0)
button:SetWidth(120)
button:SetHeight(50)
button:Hide()
button:SetScript("OnClick", function()
				ButtonC:Hide()
				ButtonA:SetChecked(false)
				ButtonB:SetChecked(false)
				end)