With electric heating it's 100% efficient at the point of use. Meaning that the energy you use = the heat that you get. Use 1kW of electricity and you get 1kW of heat. So with options 1 or 2, for room heating, the running cost will be the same for an equivalent heat output. Option 3 will only heat domestic hot water.
Gas and oil are less efficient because there are flue losses, but in their case the fuel cost is much less to start with, so despite their inefficiency, the running cost is much less.
If you want a cheaper form of electric heating there are two options to consider that you haven't mentioned:
1) Storage heating (economy 7 or 10) Here, the actual electricity usage in kWh will be the same for an equivalent heat output, so you won't use less electricity, but because the electricity is only available and is 'stored up' during 'off peak' times the electricity companies sell it for much less than the standard rate.
2) A Heat pump, these can extract heat from the outside air (air source) or ground (ground source) even at very low temperatures, so the electricity is only used to move it around, hence the term heat 'pump'. With them you can get more heat than the electricity they consume, some manufacturers claim that with 1kW of electricity you can generate up to 3kW of heat. But this is under perfect conditions. There are many factors that effect this. Ground source systems are more efficient, but you need a lot of ground to install the outdoor pipe system. Whilst with air source heat pumps don't have this requirement but their efficiency is not as good and it drops the colder it is outside. They are also expensive to buy, particularly the ground source version, and they need specialist installation.
