The amount of heat produced in an electric circuit depends upon the current ( $I$ ), resistance ( $R$ ) and time ( $t$ ). If the error made in the measurements of the above quantities are $2 \% , 1 \%$ and $1 \%$ respectively then the maximum possible error in the total heat produced will be\\
(1) $1 \%$\\
(2) $2 \%$\\
(3) $6 \%$\\
(4) $3 \%$