Fact 1: An electrical insulator slows the transfer of electricity. Fact 2: Tires are electrical insulators. Given the two facts above, what slows the transfer of electricity more?

Available choices:
(1). sweat
(2). Alcohol
(3). Smoking
(4). tires
(5). copper
(6). air
(7). water
(8). oil
The answer is:
(4).