Which of the following statements about phenol-formaldehyde resins are correct?

1. APhenol can react at its two ortho and one para position, so each ring can link to up to three others.
2. BA resole carries hydroxymethyl groups and can be cross-linked by heating alone, without further formaldehyde.
3. CFully cured bakelite is a thermoplastic that softens on heating.
4. DA novolac needs a cross-linking agent such as hexamethylenetetramine to form the final network.